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ns chemistry «bows Uk that mighty and vain man not much to boast of. His insignificance becomes apparent when we reflect that water constitutes threefourths of his body, and that of the 431b. of solid materials that bnild np the hnnian fabric, most are uni"▼ersally diffused throughout creation. A lesson of humility oueht indeed to be learnt from the inspired ^rords "Oust thou art, and unto dust thou slmlt return." During life a constant destruction, a never-ceasing wnsto of all parts of the body is taking place. From the first moment of onr existence to the last day of our lives these incessant changes are never for a single moment suspended. Wo cannot wink an eye, move a finger,see an object, hear a sound, or indulge in a thought without a certain portion of onr hubstanco being sacrificed. In fact, so rapid is the wear and tear, that physiologists calculate that a quantity of material equal to the weight of the entire body is thus removed every forty days; so that in that time we may be said to "moult" or cast away onr old body and have a new one. This constant wa*»te, resulting from the various chemical, mechanical, and vital actions to which the living organism is subject, must be compensated by the introduction of new materials from without, otherwise starvation would ensue. First the fat disappears, then the muscles shrink, soften, and decay; next the brain becomes attacked, and delirium and death complete the series of events. It is by the agency of our daily food that these looses are repaired. Now it has been found that the "principled" contained in the human body also exist more or less in onr various articles of diet, hence it is easy to understand how readily food becomes " assimilated '' or converted into the substance of tho body, thereby fulfilling the conditions most conducive to our health and happiness. Beta.


[148J Silt,—He is a bold man who takes up tlu cudgels with such an opponent 0% "F.R.A.S." And, but for his invariable courtesy, I am not s-ure that I shonld do s». In reference to " Curious Question" (p. 878', the gun, the ball, and the earth are all travelling eastwards at 1,000 miles an honr on a circle of 4,000 miles radius. If sufficient powder and elevation be given to keep the ball iu the air for ten seconds, and there/ore, to mnd it to a height of 5,456//., or a little more than a mile (we may take the ball to he practically at the height of a mile for nine out of the ten seconds) the ball will have to travel eastwards over a greater circle than it started upon in the ratio of 4001: 4000 for the space of nine seconds; retaining the original velocity (1,000 miles au hour) and will therefore be left behind (westward).

The gun will in fact be gaining on the ball at the rate of quarter of a mile an hour fur nine seconds.

Tho sum therefore stands:—

Hour. Seconds. Mile. Yard.

1:9 :: 1 : 11 an amount of "westing" invariable, whether the gun be tired perpendicular or at any angle, N., E.f S., or W.

The theory of projectiles iu high latitudes is more complicated. T. S. Usuuune.


[149] Sin,—A maxim I strongly hold to and endeavour to practise is to learn something every day, so that I am always ready to modify any opinion whatever, if further experiment or thought shows that it is right to do no, but Mr. Haines (p. 402) has somewhat misconstrued my expressed opinions in supposing that I have changed them as to the use of iron in batteries.

I have very strongly condemned iron as a negative metals-that is, its use in place of platinum and carbon in nit 1c acid and other batteries, but in tho case in qne&uon it is to be used as the positive in place of zinc, a use perfectly well known, but condemned by general practice in most forms. When used it should always be as sheet not as cast iron. The objections to it are very simple ; its electro-motive force is lower. Thus I have used it in place of zinc in the bichromate cell, but, of course, it gives a lower current; in every other point acting perfectly. Now, turning to tho calculation (p. 387), it will be seen that the cost of the zinc is only about one-fourth the total, reckoning it at 7d. per pound, double what it may readily he got for, as I buy it at 34d. If we reckon the iron at Id. only, the difference of cost will not bo a very large proportion of the whole, wliile the current would be considerably reduced in force, and thus it becomes very doubtful economy.

In simple acid cells a very serious objection U the fetid unwholesome gas given off, owing to the carbon and phosphorus of the iron producing fumes, which sicken me more speedily than any of those which frequently pervade my laboratory.

Nitrous acid fumes are acted on by iron solutions, but in nitric acid cells only a small part of the action produces these, and I believe that tho proportion of gases given off or absorbed depends greatly on the rate of action. On short circuit, as when I tried it, tho gas seems to be given off very nearly as freely as from a nitric acid cell with zinc, yielding the same current.

The blue colour given to nitric acid iu the action of the Grove's cell is not a ferroeyanuret, as Mr. Haines suggests, because it iR produced in the absence of iron; it is considered to bo due to the solubility in the nitric acid of the lower oxides of uitrogeu produced, and which when the acid is saturated are given off aa fumes. This resulting solution is more freely conducting than the acid alone, which is the reason that the current rises in force for some time.

In concluding, I would urge upon* readers to follow Mr. Haines' example. We have plenty of absurd and crude "suggestions and inventions" of no value, while little observations as to workings and actions are always useful and suggestive, and reward their authors by fixing knowledge on their minds. Sigma.


[150J Sib,—Noticing some enquiries in your journal lately, relative to the above, I jot down, for the information of tyros in the sport of angling, a few necessaries, the possession and the proper use of which will enable any of them to get good sport wherever fish are to be found. Few anglers care to have what is called a general rod—no doubt it saves troublo in carrying— but it is sure at some one time to be either too short or too long, too stiff or too supple, or too something when an emergency occurs, and in no other sport do emergencies occur so often as in angling. Therefore, I would always recommend anyone wishing to become an angler to have a rod that Buits tho fishing he is desirous to engage in, remarking, at the same time, that when he gets expert at his business he is never taken at a short, no matter what rod he may bo using, I have known a first rate fly-fisher, when whipping for small trout with a single-handed light t!y rod and a line line, hook a large salmon, and land him safely. For a trout stream, at widest part not more than 18ft., a light single-handed rod of lift, or a few inches more or less is just the thing. This may be made iu thr«e pieces, or four, and as I have made all my rods from the one material, a description of one does for all. The butt is composed of well-seasoned ash without swirls, and straight in the grain, it may be hollow if desired, to hold an extra top; tho second or middle piece made of hickory, and tho top made of laucewood, finished off with about ltiin. of split bamboo. If the rod is in four, the two centre pieces may be made of hickory, stained any colour, and well varnished with coachmakers' varnish.

A rod for trolling for pike should be stiff, and 15ft. to 17ft. long, furnished with stand-up rings to permit tho free passage of the line in running out. This rod will also do for trolling for the great lake trout {Salmoftrox) iu the lochs of Scotland.

A salmon rod shonld be lMft. or 20ft. long, in three pieces, and should have two spare tops. If an angler lives close by a river this rod is better spliced in one length, as the bniHs ferrules hinder slightly the free play of the rod. Living at a distance from a river necessitates joints, but most good anglers prefer to splice the top and middle joint when they reach the scene of their labours—this may easily bo done with a piece of well-waxed end.

A reel for a single tly rod should hold about 30 yards of line line, made from silk and hair. Tho line for pike or trolling for lake trout may be made from hemp either twisted or plaited, and afterwards well varnished. A salmon line should be 100 to 120 yards long, very strong but light, beat to be made also of silk and hair. All these lines should be purchased at a first-class tackle makers—one who can be depended upon to give a good article. It is dreadfully provoking to lose a tine fish through tho breaking of u rotten line. Very hard-twisted lines, although they look smooth and strong, are apt to be brittle, owing to the hard twisting causing the strands to cut each other. Boiled linseed oil, often used to varnish lines, has a tendency to rot them, owing to the manner of preparing it. Raw linseed is, if obtained pure, about as good a varnish as can be used. All lines—good ones—are expensive, but if eared for will last many years. Make a point to have the lines, carefully dried after using; nothing so bad as allowing them to remain on the reel in a wet state. They may be easily dried by drawing them off the reel in loose coils on tho floor, or coiling them round the backs of two chairs. Tho joints for rods I recommend to be tongue and socket joints, with a bra,-,s bent pin attached to each piece near the joining, around which a strong silk or linen thread may be lapped to prevent the joints separating when the rod is iu use.

The flies next demand our attention, and hero let me say, that it is quite a mistake to have a largo stock of these, as after using flies once or twice they lose all their pristine vigour; and if they lie by for a season are apt to suffer damage from the moths. Therefore, it is preferable to buy a few of the sorts wanted before going on any fishing excursion. Most rivers have favourite flics, which may be the means of filling a basket sooner, but in the hands of an export angler the few standard flies I here enumerate will do all that is wanted—give sport, and fill the creel—and can be had at a moment's notice at any tackle shop. Hare3 Lng, March Brown, Red and Black Hackles, Blue Dun. Wren Hackle, Grouse Hackle, Partridge Wing, Green Drake or May Fly, Grey Drake, and the Francis Fly. Salmon flies have different names iu different localities —the Butcher, the Doctor, the Professor—all Borts, shapes, and colours. Lake or white trout flies are about half the size of a salmon fly generally, with crimson or purple body, and green or yellow wings.

The baits for trolling are very numerous—both live and artificial. I could not enter upon the manner of hooking live or dead bait in the limits of this letter. Artificial minnows do very well, especially for the 8almo ferox. The spoon bait or archimedian spiunor is the best for pike ; a landing net is requisite for tront fishing, a gaff for salmon or lake trout. The casting lines for salmon are composed of the strongest gut, and should be from 8ft. to 0ft. long; the casting lines for tront should bo of fine gut, and may be only JJft. long. In trolling for pike or trout, the bait should be fastened to a gimp trace, with at least one swivel to prevent fouling. The

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[1511 Sib,—Would any one of our many riders n know how, or has himself preserved fruit* kindiv safe known through our journal the motiu* opermmdi* Tj particular point ou which I wish for information i^fe* the tin cases which generally come from America, cc; taining peaches, are hermetically sealed. 1 wished v preserve strawberries in this way, and so I filled a tici-sv with them, putting in a little sugar and two or tbm spoonfuls of water. I then soldered on the top, learnt of course, a small hole. I put the case then on a ria fire, in order to get the case filled with steam, wfcT-v when I felt it boil, I took off, and sealed with a'drcv: solder the small hole.

If I thought this was the right method, I *■■■.-' make up some more; but to find when I came to ow them that all were spoiled would bo rathor dialpointing.

Did I do wrong In putting any sugar in? I eonU not get the Bteam to come out of the small hole in i \ jot so that I oonld see it, unJe-w tckt-n I sV»o£- th* ca*e. I was afraid to boil it long, i.e., more than t&n minnte*, for fear of softening the fruit.

Also, could any one tell me how fruits, and, J be/iere, even flowers, are candied? I believe the method, which is French, is kept a secret.

Dehf E React.


[152J Sir,—I have been making experiments ou the horizontal windmill. I have made models ol those, described by Mr. Vallauce and by "Rustic trom Berkshire Downs," and, as fur as my experiment* have gout*. I think, for practical purposes, Mr. Vallance's ia mucb the best. Its motion is very smooth, and not likely u> cause the same amount of wear and tear a* the "Rustic's." In the latter the shock to the arms on ti» change of the sails from the horizontal to the vertaa/ position is very severe unless he can break its fars-cj interposition of a spring. I mean to compare tka as to the amount of power given off for the «a& surface of sail. At present, I think tho •• Rustic'*" U the most powerful form of sail; but this i*. counterbalanced by the jerking motion, the digk-Gii" ■. properly fixing the pulleys over which the rop*. jasec the opposite sails passes, and by the severity * '** strain which the arms are required to bear.

Another disadvantage is that the whole power * erted ouone side of the mill, whereas in the Yalta* construction the sails ou both sides of the mill ma;* *^ at the same time, and thus this form approaches &< nearly to the vertical mill.

Plus H. W. Reveley evsr seen a horizontal m£! i the one he describes on page 40 in actual week. ~J proportions he gives seeui very large for wo little jv*lie seems to be mistaken about the open kf^-* sails, as he says "tho wind only catches one saJ «* time, and that only for an instant, beside* the i*ap** difficulty of getting thee ail frames back *£*J-r * wind." What does he mean? there is no in^wi difficulty. In all forms the sails come back wc13**1 edge to the wind. There is no such great di^r&r- ,JS> the vertical, for then, too, the edge has to n^"^33*5 the air, and that it all that the edge of fnrn to ° do in the horizontal, and a little consideration « ¥:• Reveley's part wonld have shown him that tht t-foT though he may say one sail has to come up wsi«> edge aoaiwtt the wind, and so cause more resistanrt lac the edge of tho vertical moving in what may V ** garded as still air, still, he must not forget that » balance this resistance tl ere is ou the opposite ant' sail moving with its edge with the wind, so that th- ~ Bistance from this cause : s reduced to nothing.

I should like much to 9ee some more disonssiax « the horizontal windmill. With the exception of * Vallauce, no one who has written has stated thai ■» mill did any real practical work. "Rustic frbm B*-» shire " has not fulfilled h s promise to send drawing- "his more powerful mill, v hich ho speaks of in hisl<"v: on page 18 of this volume. I mean to make n miXL, aa< therefore, any farther information as to practi^J wcrting would be most acceptable. Mr. Vall&nee fc*> already given me much h elp, and I think the sab}** of a cheap motive power s well worthy of a i>hxot» i* our Mechanic. Dsar Ewuc.


[153] Sir,—I beg to 1b y before your readers mv criticism on "Astronomical 1 otes for July." We find ttf moon comes to the conju iction of Jupiter at 4b. &itej-.

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tndRo«at3h.5'2m.intheaft6rnoonofthe24tli. Mercury '~fM( in superior conjunction with the sun on the 28th, Imp is in conjunction with that luminary on the 27th at Bh. 2'Jni. a.m.

Why has "F.B.A.S." discontinued to give us the t irac of rising or setting of some of the planets?

It must be acknowledged by all, that it is far more oonsouant with reason to give us the right ascension fviid declination of the sun, or the longitude in the ecliptic, than to state that his right ascension is (on tho 1st July, 1870) 6h. 40m. !>0"-i8s., and his declination 2a' 1' 22*7 ' X., and that he is "conscquttntUj" in Gemini, Ac The inference or deduction is illogical.

Why do the compilers of the "Nautical Almanac" reckon from thut important point called the first point of op? You have hiB right ascension computed from this point, as well as his longitude, Jkc.

The "Firth point of new" is therefore, as you are

plcivsed jocosely to term it, of far greater importance

than the outlines of a fabulous animal. In short, we

prefer to say that the sun is in (the sign) ra, and not

in (the constellation) 0

G. Firth.


1154] Sxrt,^I herein enclose some of my geometrical approximations inserted in the Philosophical Matjaxine, stimulated by Mr. Proctor's in your number of the Wthmst., pnge 3T6, his L G beiug simply onefifth of s/ 2. o B or O G, producing 3141421.* The lute Mr. "Willich gave, in his " Popular Tables," a nearer approach, and were my numerical triangnlet convertible to a geometrical appendage it would be very close. You perceive I found, from considering 3150000 —

ttlOOO =7S5that(3000000-8007 =A) ~igives8H15921G

20 ixud affixing (1200 - 2) A, or 35807932011, we have ir true to 10 decimals. Tho first portion is represcntable by' traciugl a semicircle, diameter 1000, applying

» 60a + 18* = L-3007 as a chord, and reducing the

supplementary chord in the ratio of the ordinntes to

lhe ahscissas of Ji and _ of the diameter, producing a 0 a

chord exactly equal to V3141502B5.

Pago 874.—Although as an old Fellow of the Royal Astronomical Society, I rejoice at the f urthor extension of the "family likeuess" between the constituents of other planets with our own, yet is it not premature to -suppose their chemical elements are exactly alike, and so as to produce the same sorts of plants aud sentient -beings, knowing as we do the immense terrestrial variety God has formed out of the few chemical elements, oxygen, hydrogen, azote, and carbon?

Page SJS0.—Metrical Act: Referring to the "Companion of the Almanac " for lb'27, page 100,1 lately deduced that (883 - -000580) pendulum lengths = Still yards per Act of 1824.

In tho Philosophical Magazine for January, 1841, I attempted to show that the equatorial circle plane of a rotating orb whoso radius from orb's centre is the cube root of ratio, equator gravity to centrifugal force at orb's surface (i.e. £/ 289 for the earth), is a limit whore these forces balanco each othor, and a molecule there will bo undecided to revolvo round or fall upon the orb. It is curious that Kepley's law applied to Mercury and the solar limits, to our moon,and ^'.i8lJ to Jupiter's moon and his limit, give from the secondaries' period

tho rotation times of the orbs | Virg. 60" : 289^- :: (27

days 7 hours) .-. (21 hours)2 J as we might see them, thus combining the sun's twenty-five days with Mercury's 88 days, earth's 24 hours with the moon's 27 days, Jove's 10 hoars with his moon's 42 hoars, and jxfrhaps thus indicating the limit sphere separating tho primary local influence from its action as acoimic body on the others. S. M. Drach.

THE MONSTER HARMONIUM OF THE FUTURE. [156J Sib,—The Tantalus cup held to my lips by your correspondent " W. T.," No. 257, page 580 (whose initials yon printed "R. T.," which will account to 'Harmonious Blacksmith" for my addressing him nnder those initials), has never heen removed. I suspected he was quizzing in proposing the scheme of an harmonium with 19 rows of reods distributed between two manuals, and 3 rows extra allotted to the pedals: and I prayed him in my letter (No. 200, page t>57), as an earnest enquirer after the most perfect harmonium that can bo suggested, to afford me, if ho was not quizzing, certain information, which, although then it was March, and now it is July, and our journal lias been deluged with the ideas of " W. T." and his old collaborateur, '• Harmonious Blacksmith," on various topics, harmoniums not excepted, my thirstings after a few drops apropos to my requirements, are still nuappcased. Despairing of a satisfactory reply, I have been compelled to treat tho whole description as a joke; othorwiso, I should have been very glad to have given an order. These sort of jeux d'esprit may serve as a liltlo amusement amongst weightier matters, for seekers after lighter literature than the staple of our journal, but answer no practical objeot for earnest enquirers.

Another thing, waiting these four months has left time to look around aud examine various models and

suggestions for models of harmoniums. I have somo of these latter in my possession which I will place at the disposal of any of your readers who have similar wants to those which I have already experienced.

I had nearly exhausted the list of names of makers supplied in your last issue (p. 899) to "J. C. P.," aud as the result of my experience I said that there are no makers of largo harmoniums amongst them; no one who attempts to introduce a novelty either in tone or in expression ; every one working on the same model, and one, indeod, I met who would rather not hear of anything now or different, and certainlv would not work to originate anything. Nearly dispirited, I took heart from reading tho advertised testimonial of Dr. Leslie in favour of the Professional and Connoisseur's Harmonium to see tho harmonium he praises. In addition to seeing it I had the good fortune to see an extraordinary harmonium the sumo maker is exhibiting which surpasses anything I havo seen in Paris, or in London, or in Leeds, or wherever I have been. I have given an order for one exactly similar, the maker intending to keep the present one some time longer for exhibition, and ultimately for his private use. Now I can realize everything" I wanted in soft and gentle tones, that is to say"by the row of keys at top. There are two rows of keys, but the top row "gives delicious notes, so soft it is ail echo, not by a breath resembling reeds. I cannot understand itj but I am charmed to find that anything can give sounds gentle without any difference in blowing. By one stop there is a very pretty beat in tho note, quite a pulse, making a wave of sound dreamy and delicious in its ebb and flow. I cannot take the bass part for reeds ; it is deceptivo enough to p:ns for wood pipes, though in the bottom row of keys there is something quite different, and moro like an harmonium. I should bo glad to describe to your readers its effects. I have nearly got what I desired as to loudness and holdnoss. My old words "rank and strident," though not strictly applicable here, picture a want felt by all musical natures. Light and shade are required in musical scene paintiug as well as in nature. I much want a trumpet stop in an harmonium, but I om informed I cannot get it. Next best to it, I find in tho lower row of keys stops of groat brilliancy and power. These taken in comparison with those at the top show a great contrast. I find a beauty there. They are not wrongly labelled. I do not know the Cor Anglais, but the violincello is perfect. Also the tlute and clarionette. The contra bassa is a power by itself unique. They are not unaptly described by Dr. Leslie, whoso words give a good guide to what you actually find in the instrument. A little pressure by the knee keeps the full power on; it is magnificent. Press thu other knee swell, and it produces an effect of piano, either on one Btop or on full power. I may say I havo found in reality twenty-seven stops and nine sets of roeds, whilst your correspondent has been playfully poking his fun at me respecting his harmonium of tho future Thanks, however, to him for his kindly notice of me as regards the sketch of the piano.


P.S.—I see that some other correspondent has the nom Ac plume under whicli I address yon. Would you kindly desire him to adopt somo distinguishing addition, or to substitute a name nit already appropriated. This I ask in order to prevent confusion.


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TRACTION.—" J. B." says:—" In reply to Mr. Thomas, page 394, tho action of a tramway in reducing the draught is, that the equality of its surface does away with the obstruction caused on all ordinary roads by rough ridges and projections which do, in fact, cause the load to be lifted over them at a useless expenditure of power. The saving of thia, which is effected by the tramway, is, of course, therefore, as beneficial on a gradient us a level, and "bite of the wheels does not in any respect affect the question when horse-power is employed, and is only needed when traction is obtained by power which rests on and draws wholly by its adhesion to the rath. It, therefore, is far easior for horses to draw a load on a tramway than on a road under all circumstances; only if the gradient be steep and the load heavy tho wheels should be chocked if tho horses are stopped, as the tendency to run backwards is as much increased by the tram as the upward draught is lessened by it."




Metallurgy," gives the following solution for coating iron with copper :—Carbonate of potassa, 4oz.; sulphate of copper, iioz.; liquid ammonia, about 2oz.; cyanide of potassium, 6oz.; water, about 1 gallon. Dissolvo the sulphato of copper in boiling, distilled, or rain water, and when cold, add the carbonate of potassa and ammonia; the precipitate, when formed, U re-dissolved. Now add tho cyanide of potassium until all tho blue colour disappears. A precipitate will be found at the bottom of the vessel, from which the clear solution may be decanted. Two cells of a battery will bo necessary to deposit from this solution. Articles of iron which are to roceive this deposit should bo previously soaked in a strong solution of caustic alkali, either soda or potassa, made by adding to either of these salts somo recently slaked limo; the clear liquor proceeding from which is to be used for the purposo of removing any grease which may attach to the article, which is to bo thon well washed and iuimnrsed in ft pickle consisting of sulphuric acid, lib.; Kvilrochloric acid, 2oz.; water, 1J gallons. After the i*Ty nfl9 remained in thispicklol for a short time it may ^Qu *Lovod,and woll washed and |

scoured with sand and water applied with a very hard brush.—Patience And Perseverance.

[2673.]—CASTING SILVER BALLS.—A mould made of iron and resembling a bullet mould iu shape should be used for this purpose. The handles should bo long and tho inside of the mould should be woll blacked over tho gas. Before casting, the mould should bo made so hot that it will not admit of being touched by tho hand. —walter J. Nicholls.

[2677.]—HYDROGEN GAS FOR BALLOON.—Taking the weight of air at ljoz. for each cubic foot, it would require about 1,970 cubic feet to be displaced to raise 11 stone weight (i.e., 1541b.). Pure hydrogen gas is 144 timos lighter than air. You would require about 140 cubic feet of this gas, but common carburetted or coal gftH is generally employed, whose density is rather more than half that of air. Using this would require about 1,000ft. To this must bo added the weight of balloon, car, and cords.—Patience And Perseverance.

[2677.3-HYDROGEN GAS FOR BALLOON.—" Henry Nntt" docs not state which carburetted hydrogen gas he intends to use, whether C H ^ or -i II \ ; nor duos ho t>ay how high he wishcn his balloon to ri*o, nor what U ita weight.—R. T.

[2G94.] — GREATER PTHAH. — Cesar Cantu " Boat. Univ." t. i. p. 194. says, speaking of Egypt, " the dogmas particular to the priests acknowledge a unique Supremo Being, who could not bo represented by corporal images. Plutarch says their highest science consisted in regarding Phta as the great architect of tho universe; they worshipped specially his wisdom at S;ns under tho name of Neit, his goo'dness at Elephantine, under that of Cnef, the symbol of which was a serpent rolled upon itself."—Bern Ardix.

[2756.]— LAMENESS IN HORSES.—In the first place, I must apologize for not having answered "J. O. Duffryn's" query sooner, but through pressure of business, and having had to leave home for a time, I have been unable to do so. As regards the above disease, the querist omits to state what stage of the disease he wished to treat. If in the first, or active stage, I should advise him to adopt doplotive measures, viz.:—Physic hall, composed of Aloes Barb.6oz.; bleeding at the jugular vein; bran or cow-dung poultices to the feet; cooling diet, rest, &c. On the other hand, if the disoase has assumed a chronic form, which it generally does, I know of no better treatment than the adoption of Mr. Broad's heavy shoo, invented especially for laminitis, or fever in the feet (of which I forward a sketch), which has lately


made its appearanco before the public, and has elicited such a lengthy discussion in the pages of the Veterinarian, Field, tie. From my own observations, aud that of others, I have come to the conclusion that it is tho best shoe extant. Should the querist require any more information, I shall bo most happy to render it.—Country Vet.

[3703.]—PASTEBOARD.—Thomas Grist should put his pasteboards into an hydraulic press. They will bo quite straight when dry.—Saul Rymea.

[3716.]— RELACQUERING BRASS WORK.—"Pro Bono " should scour his old brass with very fine pumice, thoroughly rinse and polish. The acid will no be required.—Walter J. Nicholls.

[3726.]—CHROME BLACK.—I heg to send the following instructions from Thos. Love's " Dyer and Scourer," which I have found a first-class book. He says the best way is to clean them well in soap and water, aud boil them woll for half an hour in olean water and argol, take them up and hang them up to cool, throw away the contents of tho copper, fill it up with clean water, make it boil, and put 4oz. of chrome and 4oz. crude tartar in the copper. Put in tho goods and boil well for 40 minutes, take it up, cool it, throw away the contents of the copper, and fill it up with cloau water, make it boil; put in as much logwood chips by weight as the goods weighed when dry, and a quarter as much fustic chip,-!, boil well for 10 minutes; while this last copper is getting on tho boil you must rinse the goods in two clean waters, drain them, put them in the copper and boil well for an hour, handling well all the time; then take them up, cord, rinse, dry, and they are done. Ho says some dyers clean with chamber-lye, aud dispense with tho argol copper, making two coppers do tho work. The quantity above is for 10 yards of French merino, which takes about 8 gallons to dye in. I have dyed many things by his direction and have found them first-rate. —T. K.


reply to tho query of "Natrnin" on this subject, the deposit that he complains about is soda. It is caused by the solution being too concentrated to retain it involution, and by tho heat. To prevent it getting into cakes it must be stirred continually, and especially at that part of tho pan which is exposed to the greatest heat. Does "Natruui" want to keep the soda in solution? If so, then water must be added, so as to have a weaker solution. Or does he want to get the soda in powder, as I presume ho does? Then during the evaporation tho solution must be kept constantly stirred as before mentioned. P.S.—If "Soda Crystal," who some time ago enquired of "G. E. Davis" respecting the manufacturing of this article on a small scalo, is still in want

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him with the same through tho medium of the English Mechanic—Joseph Rosjckll.

[373S.] — BAROMETER TUBES.—A little strong acid will remove every film and make them fit for use.— Walter J. Nichoixs.

[3766.] — CLEANING AND REFILLING BAROMETER,—Lardner'a " Museum of Science," No. 44, says: —When the mercury has beeu purified it is next uocessarv to render the tube perfectly clean on its inner surface. It generally happens that tubes exposed to the air, always more or loss damp, have a film of moisture upon them. It is necessary therefore to expel this. After cleaning the tube by internal friction it is warmed over the flame of a spirit lamp from end to end, so as to evaporate any moisture which may remain upon it and render it perfectly dry. Mercury is then poured in by means of a small funnel until a column of about lOin. has entered. To dismiss the air that has entered with the mercury it is heated over a spirit lamp until it is raised to a temperature higher than that of boiling -water. The air being expanded by the boat escapes from the tube. Mercury is again introduced, and again treated in the same manner, until tho tube is filled. In this process it is usual to heat the mercury to nearly the Bame as that of the tubo before pouring it in, otherwise the difference of temperature might crack the tube. When the tube is completely filled the open end is fiually stopped with the finger, and being inverted, is plunged into the small cistern of mercury at bottom of barometer. —Patience And Perseverance.

[3781.] —PHOTOGRAPHY.—I once used the wax paper process, and to change the paper made a bag of three folds of black calico one side, and three folds of yellow the other. There were two short sleeves about one-third from the bottom of the bag with elastic wristbands, and the top had a hem with running tape. I put "back" and portfolio into the bag, also my head and pulled the tape ; then put my hands into the sleeves, made the change and then reversed the process. The only objection to this is a frolicsome companion'—M. W. G.

[3787.]— TEMPERING BUFFER SPRINGS. — Tho way I generally temper them is to heat them in a slow fire with wood chips, little more than blood red, then plnnge them in water; then take and heat them over a clear fire, and rub them over with grease, and when you Bee the grease begin to show a blue flame roll them in water, and your springs are tempered.—Deeside.

[3789.]— AVIARY.—Having just comploted one forsome young canaries,I did thus:—I made the wooden part of the cage of £in. mahogany, with four upright posts and cross bars at top of same. Bought 31b. of 15 tinned wire, 21b. of 12 ditto, and Jib. of binding wire; bored the holes Jin. apart for the small wire, and Sin. apart for the cross wires,using a bell-hanger's small pliers to cut tho wire into lengths. Some difficulty will be experienced in ntraightening the wire, but that can be overcome with the pliers and passing it between the fingers and thumb; set up on one side and bind as you go; the cost will be about 8s. for materials. Look at a ready-made birdcage and take a lesson and have—Patience And PerseVerance.

[3815.]— FASTENING EMERY TO LEATHER.—The following will suffice :—Take and boil glue very thin, add a little milk, raise the pile of your leather and put on your glue with a brush, afterwards sprinkle on your emery and let it cool.—Deeside.

[3828.]—KID BOOTS.—Some time ago I discovered that my tin of harness compo emptied rather too fast. On inquiry I found that "Mary " had used it for months to missus's boots, so I began to investigate and fouud the boots (2 years old) to bo in a beautiful condition. I also found that " Mary " had applied a little regularly, taking care to polish with a soft cloth, and that it was very successful. I make my own blacking and for tho benefit of H Old Scrub," or any other man, I give the recipe. 2oz. best white wax, £oz. prussian blue, l$oz. ivory black, \ pint of spirits of turpentine, 1 table-spoonful spirits of wine. Melt the wax, over a slow fire, in an earthenware vessel, then add the blue and black, taking care to put in the black by littles at first, or it will boil over; when cool add the spirits. Stir It well from first to last. —banting.

[3828.]—TO SOFTEN KID BOOTS.—Let "Old Scrub" melt £lb. tallow, then pour it in a jar and add to it the same weight of cod or olive oil, stir and let it stand till cold—apply a small quantity occasionally with a piece of flannel. Should the boots be very dirty, cleanse with warm water. Will soften any kind of leather.— Leather.

[3881.] — STARCH MANUFACTURE. — Particulars are to be found in the "Chemical Technology of Dr. Bolley," printed In German, perhaps translated into English; volumes sold separately. Information at Messrs. Triibner & Co.'s, German booksellers, London. —Bern A it Din.

[38U.]—GRINDING DRUG SEEDS.—I have always found a common coffee-mill answer admirably for this purpose.—Walter J. Nicholls.

[3844.]—ENTOMOLOGICAL QUERY.—The larva of Cosmia traptzina is greenish, with the dorsal, subdorsal, and spiracular lines white; the spots are black or dark

freen. It is full fed at the end of May or beginning of one. It i< a noted cannibal. It feeds on oak and birch, between a packet of leaves united with silk. — R. T.

[8861.]—TO CLEAN SADDLES.—I think "Saddler" is a little too severe on my advice to "Equestrian " concerning his saddles. He ("Equestrian") did not ask for something to impart a high polish to a saddle that had been in regular use, but for a recipe to render "supple" tho leather parts of a saddle that had lain aside for some time. Far be it from me to sound my own trumpet; but I must condemn the use of turpentine and bees-wax on brown leather. And I also know that there are parts of a saddle that do " not" come in contact with the rider's clothes, i.e., "where there is no wear" (the sentence that " Saddler" comes down so heavily upon), viz., inside of skirts, inside of flaps, point pockets, sweat flaps, girth straps, Ac, and that after a saddle has been out of use forsome time, nothing could be better than to apply a little neatsfoot oil to the parts above named to bring them back to a proper pliant condition. And I also know that a saddle i-t not all made of hogskin—instance the parts above named, and I have Been saddles look a better colour and keep in better condition with the application of milk than with soft

ing harness; but think the oil would be better applied before it was quite dry. Couriers lay on the oil when the leather is wot.—Bantino.

[3875.]—BLEACHING POWDER.—In reply to " Gratus" the following is the method of manufacturing

bleaching powder:—The lime used for the preparation of this arcielo must be of the first quality, for unless this is attended to the salt prepared irom it will be very interior in colour. To prepare tho lime for the absorption ol the chlorine gas it is brought to the screening department and slaked with just sufficient water as will cause tho lime to crumble into a very fine powder; some care must be taken that not too mucu water is used, or it will be difficult to screen it. The powdered lime Is then screened or sifted through fine wire gauze sieves, having about 400 apertures per square inch. The uext step to be considered is tho preparation of the chlorine gas. This is obtained by acting upon peroxide of mangauese with hydrochloric or muriatic acid. The stills used for generating this gas are formed of large stone slab$, grooved and well cemented together, and in the form of a cistern; thU is again surrounded hy a casiug of tirebricks, iron, or stone slabs similar to tho others. A cavity of about 6iu. must be left ail round between the two; this servos as a steam chamber, and is used to heat the contents of tho still. The size of the still outside, including the steam chamber, may be about 9ft. square and about 4zt. deep. Inside of the still, and supported on pillars about In. above the bottom, is another stone slau called a tabic; on this table is placed the manganese whieh is to furnish the chloriuo gas. From the stills the gas is conveyed to the chamber through earthenware pipes; the joints of these pipes are connected together by water lutes, so that no gas can escape. Various apertures are required in the top of the stills, a large one in the centre for charging the still; other small ones for running in the acid, and another at one of tho sides and at the bottom for running off tho waste acid before recharging. This last is a round hole, and is stopped with a wooden plug. The chamber is formed of lead, supx>ortod by a framework of wood, similar to a vitriol chamber. The chamber has two doors, which are luted close during the time the charge is in. Tho bottom of the chambers are formed of tire-bricks. The size of the chamber and number of stills must be according to tho quuntity of bleaching powder to he made; the height of the chamber must be about lift. Having now briefly described the apparatus and tho use of them, I will proceed with the manufacturing process. Tho first step consists in charging the chamber with the powdered lime to a uniform depth of from 4in. to 6in.; after this is done the doors arc closed and luted, and it is then ready for receiving the gas. The stills are now to be charged by placing the manganese on the table in the interior; the muriatic acid is run in until it reaches about 3iu. or so above tho manganese. The covers must now be placed over the openings and securely luted with clay; steam is then turned into the intermediate space so as to he it the contents. In a short time tho gas begins to evolve, and passes through the pipes into the chamber. The charges arc usually worked off in a period of twenty-four hours, after which the stills are emptied of their contents, and another charge of manganese placed iu. During the time that elapses in emptying and recharging the stills the lime in the chamber is stirred about, so as to expose a fresh surface to the influence of the gas. It is usually performed by the men, who go inside and stir tho contents with short rakes, uutil it is completely mixed together. The surface of the lime is left In furrows caused by the teeth of the rake. When this is done the doors are closed and made secure from the escape of gas, acid is again run on to the manganese as before, and steam turned in as previously mentioned. The lime is left in the chamber until it is sufficiently impregnated with the chlorine gas, that is, until it contains from 3U tj 37 per cent, ol chlorine. The time occupied iu doing this depends ou, first, the quantity of iimo placed in the chamber, because the thinner the layer of lime is tho sooner it will be complete ; and, secondly, tho quantity of gas passed into the chamber, but perhaps four days may be the average time iu preparing it. Wheu thoroughly impregnated, and if the still is not worked off, the gas from it is turned into another chamber, tho chamber doors arc then opened, and, as soon as it is convenient to enter, the lime is packod iu cask-;. I hope this information will bo of use to " Gratus."—Joseph Ell.

[388S.]-ALARUM FOR DUTCH CLOCK.—If "Amateur Horologist" will pay a visit to any country clockmaker, and examine a Dutch alarum clock, he will learu more iu ten minu'es thau he would from any description, which would bo practically useless without figures. —R. T.

[3333.]—PRECIPITATING GOLD.—Chloride of tin will precipitate tho chloride of gold, and ammonia the oxide.—Walter J. Nicholls.

[3919.]—GALVANIC BAND.—Surely "W. A." has neglected an essential element in the success of his baud by omitting to enclose between the strips of metal a strip of cloth, which might be charged with some deliquesent salt, such as Epsom salts, or chloride of calcium. —mat nix.

[3926.]—FORCING WATER.—" B. 8. M. G. H." would not gain anything by trying to persuade his water upstairs, let the gradations be ever so gentle. It requires a certain force to raise a body through a given height, and as far as economy of force is concerned, the shorter the route the better. Iu his own case the lengthening of the pipe would be an actual disadvantage, as the friction of the water-flow in the pipe would be multiplied six-fold.—Matrix.

[3934.]—ORGAN ACCORDION STAND.—If "Sigmatau" will look in No. 153, page 616, he will And a drawing and description of stand by " B. F., jun.," which I think will suit him, as it is very simple and easy of construction.—K. T. Z.

[3947-]—HARD WHITE PAINT.—" T. S. U."—The only conceivable way of reconverting scales of old white paint would bo to grind it with oil between the stones of a regular paint mill, or by hand between two flat stones, the under one large. To apply an alkali, in ordor to dissolve out the highly oxidized oil, would inevitably destroy the article as apaiut.—Matrix.

[3962.]—WHITE LEAD.—It la exceedingly doubtful whether " H.'s" white lead contains auy white lead at


all. The pure article is the carbonate of the metal, a its commercial value in the dry state averages front & to 36s. per cwt. The adulteration of white le*J. account of its high specific gravity, would have b rather difficult were it not for the existence of a ce mineral nearly corresponding with it in this and of very little use in the arts otherwise. sulphate "of barytes, a ponderous, massive, tr^H mineral, occurring in extensive veins, permeating «4i volcanic rocks. Two important veins of this desafefr] tion occur in Scotland—one in the island of Arm.ix,Fj4' of Clyde, the other at Muirahields, in Ayrshire—ho'.b rf which are worked mainly for the purpose of aduZrae. ing white lead. A few years ago, I carefully exami^i the workings of tho vein, and also the proees-s of Eult-.facture of the adulterant at Muirshields, which hare tv-*, in progress for many years. The vein is almost mr, cal, having an inclination of probably 5- or 7 , lb upper edge cropping out on the surface in a perfect:; moorland and mossy district. Tho gradual progxes. .' the removal of the barytes has left a considerable piy behind the actual operations, from which I ascertain as nearly as I can recollect, that the vein vara a thickness from 1ft. to 5ft. The direction oi the r* x dyke, as it may be called, extend* nearly east aarf«£, crossing the Frith in the direction of Arran; m.nt&rcan scarcely be a doubt that in the dim vLsta* •( &s past, long ere Time's erosive tooth had gnawed oc ta* deep and tortuous channels, the far-re achin g rodu. .*craggy, savage glons, the endless succession of heitb~r< clad mountains, and the lovely isles which &i±> up the matchless scenery of our lovely Clyde, th.-i fragmentary scams of barytic rock formed y-:t grand dyke, on the extent of which it would be artless to speculate. Barytes thus iound is generally k«s or more discoloured hy streaks or blotches, Ot-.l; mainly to the presence of oxide of iron. The minenl aftor being deposited at the works, is crushed tu * 6^ powder by means of ponderous iron rollers, revolve; with their edgo resting iu a large circular iron pc similar to the arrangement employed for the grindir.:' loam in a foundry. After having been thoroughly groou the mineral is digested in very dilute sulphuric »cid.. rather in water strongly acidulated by that acid in i*zx or vats, which should be lined with sheet load. Tb digestion can be repeated with frequent stirring* usi the bleaching is completed, and all trace of the to: can be removed by repeated washings and decantsti* after settlement. The pure barytes thus obtained ■■ now thoroughly dried in auy convenient manner, aui in this condition is ready /or market. It now otily remains to be told that the manu/acturers' white Jo-ad of commerce is made up by mixing the two ingredient* .in very various proportions to suit the pocket of the buyer, or tho conscience of the dealer, those proportions varying from probably 75 per cent, to almost sero of the genuine article to the corresponding complement of the other. I need not explain that all this is performed in tho ordinary paint mill with a sufficient admixture of oil. Taking the value o! pure white lead at S5s. per cwt. and that of barytes at £3 per ton, the margin tor profit will be at once recognized. Now, aUhaaga harytci resembles, in a remarkable degree, white lead, -jet, being essentially crystalline in character, and hence translucent to a certain degree, it does not, as a paint, corer so well, nor yet does it mix or combine in so kindly a manuer with the oil as the more nocculeat h^t So that "II." should not be surprised if hu lead hsi split partnership with the oil and become a *Jad mass. I have already said that this baryte-- las few applications except as an adulterant; it- hi^h specific gravity alone being often taken adn^tatfe J under cireuinstances which would scarcely Vs anticipated. I will just refer to one instance forthebtnen*. of our ''Harmonious Cotton Spinner" (I think we have one) and his congeners. The little paper tubes a=?i f-.ff placing ou the spindles of spinning mules, and Vsjm receive the first windings of the yarn, forming is cfrrthe bottom of tho cop, are made by rolling upon a iy» sheets of paper pasted on one side, drawn off ikt rsr, dried and cut into suitable lengths. Now the pw wi iu this little process is amply charged with baryta, us spinner, although in the first instance defrauded e? ~* tube maker, has good reason to wink at the deetvti'/as he, in turn, disposing of the tubes along *ntli te yarns, at maybe some shillings per pound, ben<3:^ the extent of the difference. The mineral barytes i" compound of the metal barium, oxygen, and sulpfcc acid. Bv mixing it in powder with charcoal, ani * jecting it for a time tin a crucible) to the heat of s 5r nace, it becomes reduced to the sulphuret of b«5* having lost its oxvgen. In this conditiou it hi aa> acted on by nitric acid, for tho formation of xritrtit * barytes, a salt used by the pyrotechnist in the prstt ( tion of green fires. This fact will point out to "E. he possesses one, a ready means of testing th* prr*^of barytes in his white lead by means of th* tAnr-ptt*, as a small piece exposed to the flame woaW -3" ^ characteristic green flame similar to that *>' c*W*" i or still nearer to that of iron, but not »- •*>Alexandra.

[8990.]— YELLOW DYE.—" A Countryman*_*■** try Manchester yellow, otherwise known as Ssynv^v laminc yellow, to be obtained of most choinists aua Sr;salters.—Saul Rvmea.

[4010.]—MELTING AND CASTING METAL.-' Bristol Amateur" should get some metal from a Aft typer's. As a rule, it is slightly harder than type s;rwhich is made of three-parts of lead and one of anli:^ Failing to obtain this he must add bismuth to • ordinary type-metal, till he gets the cast as hard « * wants it. The metal must be perfectly fluid, Bo if* run easily into all the crevices of the designs; b*' obtain a thoroughly sharp cast a proper castingmust be made. This may be either made to dip 0 the molten fluid or be so constructed that the fluid "* be poured in. It consists of an iron tray made witi: * closely-fitting lid kept in position bra screw, and faa^ the corners cut off to act as inlet holes. Into thj« ay the design should be placed "face" downwards; tt-j lid screwed down so as to leave the required, gp&cr- v< thickness of casting; and the casting-box inserted bv the molten metal, which should be done in a ilia^ ^ ■ direction to allow theair to escape at tho upper corner The other method consists iu having a thick Iron be with one end open, made to unclose longitudinally, ileaving space according to the thickness of the ca-1.' which it is designed. The mould is then fastened on tin Bide of this, the box firmly closed, nud placed b

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between the

POTTERY.—In bilking china and other pottery ado o( clay specially prepared for this purlaced in different parts of the "kiln," these change in colour according to tho heat of the ■* trials" are drawn out with n long iron rod e hiking, and when one of the desired colour is , .ho "kiln" has the required heat and the goods _ properly baked, the fires are drawn at onco, and it is allowed to cool.—Esaitchare.

j4144,l_FIRE CLAY.—Fire clay cannot he miule, but i« aot out of the earth the same as coal and other ñ«iríei-»l3. "Amicus" can buy it. He will lind it beet to bias bis pipes from some dealer in building materials in Ыз own neighbourhood.—Esaitchahb.

[420S.]-BALANCING LOCOMOTIVES.-By this I »appose •• Staern" means putting weights in the wheels to balance the moving partsof the machinery

For that

and expenso to him to do it himself, and would cost comparatively little.—J. R. D.

[4253.]—TODHUNTER,—I think the meaning of tho quotation is that the symbol It, and never anothet »ymbol is used to denote the ratio of the circumference to its diameter. Circumference = diameter x ir, or circ. R = 2 R « », honcc the half of the circumference = R у n, and if the radius = 1, the half circumference = », but the half circumference = 180° = 2 right angles, hence we may represent two right angles by ir, but this 1b not invariable, as others represent it by 180° or by H (hémicycle).—Bebnakdix.

[1262.]—CORNISH ENGINE.—Additional to "F. P.'1 1 bend tracing of cataracts of Wicksteed engine at


шгрояе the simplest way for an msulo cylinder engino with no coupled wheels is to put in the driving wheel, a weight equivalent to three-quarters of the total weight of the moving parts inside the frames. When there are coupled wheels, thev are so keyed on to the axles as to be in opposition to the inside crank, and, consequently, the weight of the outside rods must be deducted from the weight as found before; and when six wheels arc coupled the outside weight so nearly balances the inside weight that usually no balanco weights are required. In the caso of outtide cylinder engines, the whole of the weight of tho piston, rod. cross-head, connecting and coupling rod», nud cranks, has to he balanced as far as ia convenient, and usually equally in all the wheels. I bave given but a mere skim of the subject, but if the Editor thinks the subject of sufficient interest, I shall be clad as soon as I can tínd time, to contribute a paper on the subject of balancing moving machinery.—Q. Q. R.

Г4206.] — CHROMATIC FAIRY FOUNTAIN. — Professor TyndalL in one of hie late lectures at the Royal Institution, showed that if a ray of light was directed and concentrated Ъу a lens upon the point may of issue of a horizontalÄi/ Jet, Bomewhat in the шап-Ш пег shown, the ray of ligh if/// would not be able to leave« the falling stream of water notwithstanding that it

was curved, so that the stream was illuminated throughout its whole length. The same principle can bo applied to illuminate a vertical fountain by a slight alteration in the apparatus and arrangement. In the sketches annexed, A is an ordinary " magic lantern," with the lens placed so as to concentrate the light on the jet D; to accomplish which the box C, into which the supply pipe В enters, must have that aide opposite the jet formed of glass. For the vertical jet a plane mirror E will be convenient to change the direction of the ray. Coloured glass elides can bo inserted atpleasure between ШеД flame and the water box, and with a little scheming I think that it mighr be made very effective.— Q. Q. R.

[4211.]—SILICA, OR WHITE FLINT, can be had from T. G. Green, Gresloy Pottery, near Burton-ou-Tront, or from any of the potters in the Staffordshire potteries.— Esaitchare.

[4215.]—COLOURING TILES.—I do not think tho tiles can be permanently altered in colour (after they are burnt) except by re-burning them, and colouring them in the ordinary way before re-burning them.—Esait


[4218.]— FIXING TUBE OF LEVEL.—" Apprentice" should hollow out tirg pieces of cork tho samo shape as the ends of his tab*, and also to fit tight into the hole in the wood; then ■ ply a little thin glue and press the whole in the wood until it comes perfectly true. If done in this way, it will not break although*it get a fall.— Banchory.

[4218.]— TUBE IN SPIRIT LEVEL.—Take off the brass plate; clear out tho recess in the wood; see your tube fits in very easy. Take a little white lead or putty, flace it on the bottom of the recese; cover with a small strip of white paper; put the tube in; press it down until your brass plate will go on; try your level both ways on a surface plate. When you nave got it right, be careful to put the brass plate on the same way you took it off, and the job is finished. All good tubes are marked either at the end or in the middle. Care should be taken to keep the mark at the top.—Good Words.

(42x5.]—ICE.—Has a "Warm Countryman," or any one else tried Toselli's ice machine—a very simple way of making ice. Ice creams, Ac. If so, perhaps ho will lot your readers know the results, and whether the cost is too much.—Anon.

[4226.]—DOUBLE STOCKS.—Tho reason why doubleflowered stocks never produce seed is, because in a real good full flower the stamens and pistils are transformed into petals; hence it is minus seed-producing organs. In saving single plants for seed, it is a good plan to thin the blooms, so as to leave (say) half a dozen on each plant, and to give plenty of manure, but guard against an excess of moisture to the roots. They should be plauted so as to receive all the rays of the sun poasible. If " Saul Rymea '* carries out the "above, ho may get 75 per cent, double flowered.—Й. Rogers.

[4234.]—THE SMOOTH BLACK SURFACE ON SEWING MACHINES is given by japanning, and is a trade by itself, and if "J. W." has a machine he had bettor give it to a japanner, as it would be a deal of trouble


which is a cross section to show action), and are worked from below by side rods R R to a cross head C, with a turned bright weight T on top. As the piston P rises the water comes up through the valve V, and the air from above the piston escapes downwards through the side passages shown. As aoou as the pi-ton is allowed to descend by the commencement of the "outdoor" stroke the valve V closes, and the water escapes by the cock E faster or slower, according as the cock is more or lues open, which is regulated by an endless screw (not shown) working in tho worm-wheel W attached to the plug or "key " of the cock E. As to parallel motions, "F. P." will find them fully treated of in " Hann on the Steam Engine," Part I; price 8s. (id.; Weale. But I send him a tracing of half of the beam of the Wicksteed engino to explain a little of the matter. А С is half the beam; С D is the main link, 5ft. long; В E another link, also 5ft. long, to which the air pump-rod is attached at F. J H is another link for feed-pump, and corresponds to the link for plug-rod in и F. P.'s " question. Now, the first rule to remember is that D F H A must all be in a straight Une, or, which is the same thing, С D, В F, J H must decrease as they get nearer A, and you may have a dozen of them, if necessary. The next thing is to make F move vertically, and then, because A G is a straight line, and all the links С D, В F, and J H are kept parallel to each other by the parallel bars D E and L H, or, if you like it better, E R, therefore D E К will likewise move vertically. Now, to make F move vertically, vou have only to make

GExEF = BFxBA. Now, in this case А В = 8" Ц = lülj''

В О - в" il - 83, and CD = Gil- = 60in. Now, by rule of three, as

А С : С D :: А В : В F

1841 : 60 :: 101}: 38, and F E is 60 — 88 = 27in. So, to find G E, which m BFxBA wehftve 83_y_J01¿ m niin iQi Лв

E F 27

length of С E tho radius rod. Another way to get the same result without calculating В F first is to say


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East London Water Works, Old Ford, which stand on a floor far below the cylinder, one on each side, and aro both worked together by the plug-rod, which comes straight down from tho beam; the action being as follows: As the plug rod comes down, the chock С catches both tho cataract lever LL, and turning the wheels W W, which by chain and lever raise tho plunger P an d tho counterbalance weight T. As soon as the engine begins to "go out of doors," the plunger P descends under the action of the weight T, and this descent is made more or less rapid, as desired, by opening or closing a cock under the plunger by mcaus of the r0d R. Tho other rod S has a loop at tho lower end, and when tho stud V reaches the top of tne loop, the rod S rises and opens the valve to which it is appropriated. One of tho cataracts opens the equilibrium valve, and the other opens first tho exhaust, and, after a sh >rt interval .the steam-valve. These are all closed ag lin at the proper times by chocks on the plug rod catching hold of horns on the different valve levers as the ougine comes " indoors." When the cataracts are placel on the engine floor they are made uruuuientul (sec Üa\ 2j,


ВС 83

radius rod in the drawing from which I take the tracing is 1-,'iu. or too much, which accounts for what I think I remember used to occur at the end of the indoor stroke of that engine — vis., the plunger used to vibrate sideways. The piston rod is not fixed vertically under the end of the beam, either at half stroke, or when the beam is up or down, but midway, and the way to And the fixed centre of the radius rod is to place the beam half way up above the horizontal, and strike a circle with the length of radius rod previously calculated, taking the centre of fnston crosshead as the centre of circle, and then putting the beam-end as much below the horizontal, strike another circle with the same centre and radius, and where the two circles intersect will be the radius rod centre.— J. K. P.

[4264.)—MATHEMATICAL.—Let "Schoolboy" read Tate's "Exercisesin Mechanics," orNewth's "Mechanics" for information similar to that required to solve his question.

Let h = height of water = 18ft.
b = breadth of gate = lift.

с = centre of gravity = — = 9ft.

then area of gate = 18 X lift,
and pressure = 18 x 11 x i) x 62'5 = 111,3751b.

C. H. W. B.

[4264.]—MATHEMATICAL.—The pressure of a fluid upon any plane in contact with it is equal to the weight of a column of the fluid whose base is the area of the given plane, and whose height is the depth of the centre of gravity of the plane below the surface of the fluid. The pressure on the gate (supposing it a plane) will therefore be equal to the weight of a column of water 18ft. by lift, area and 9ft. high—18 x 11 x 9 = 1,782 cubic feet. The weight of a cubic foot of pure water is l.OOOoz. avoirdupois; so that 178,200oz. or 4 tons ltícwt. Iqr. 211b. 2oz., is total pressure required.— Ignorant Irishman.

[4272.]—CRUCIBLES.—"Student "will find the best way to anneal crucibles by making up a coke fire, and before the fire is lighted place tho crucible on the cold fuel, light the fire, and let the crucible remain until all is quite cold. I think " Student" will find the Hessian and plumbago crucibles arc the best for most ordinary purposes.—A.J. Jajiuan.

[4276.] —GUTTA-PERCHA may be rendered sufficiently soft and plastic by immersing in boiling water to be moulded to any desired shape, which it permanently retains upon hardening.—Harry G. Newton.

[4278.] — FRENCH METHOD OF DETECTING ADULTERATION OF OILS.—Mr. Heidenreich, a chemist, of Strasbonrg,proposed in 1841 to distinguish fat oils from each other—a, by their odour when warmed, b, by their colour by contact with sulphuric acid at 66° В., с, by their specific gravity. By tho first process, the oil being heated in a porcelain cápenle over a spirit lamp, the peculiar volatuc odour of fish, linseed, or other oils may be detected, especially if compared in tho samo way with unadulterated oils. For the acid test, from ten to fifteen drops of the oil are dropped upon a piece of glass, underlaid by white paper, and a drop of sulphuric acid is brought in contact with it by a glass rod, two different reactions are obscrvod—viz., when the acid is reacting with or without stirring up the mixture. The following reactions are indicated by Mr. Heidenreich—first, without agitation of the mixture, second, with ditto. Rape or Colza oil—first, greenish blue aureola, with light yellowish-brown lines; second, greenish-blue. If five drops of the acid are added the whole becomes almost brown. Olive oil—first, pale yellow passing into greenish-yellow; second, yellow, more or less gray. Linseed oil—first, dark reddishbrown, afterwards brownish-black; second, brown-black. Whale oil—first, red, passing to violet; second, brownishred, passing to violet. Se$amumoil—first, red. Poppy oil---first, yellew, or greenish-yellow; second, yellow on white or grey ground, Ac, лг. An unadulterated oil of the saino kind should always be examined with thft suspected one. The characteristic reactions vary also eomewhat according to the age of the oil. Other particulars, seo "Dictionnaire des Alterations and Fulsiti~ catione," by M. A. ChcTftllier, Paru*, 1870 (op. 4171 Vql Ц


men c he. Leipzig, Iboo, p. aiu. ■juaraciensuc reactions of some Indian oils, see "Technologist," t. ill., p.343, I think particulars are also to be found in the works of Dr. A. Hill Haasall.—Bkbnardin.

[4279.]—GAS METER.—The dry gas meter is to be preferred to the wet gas meter, for many reasons. In a wet meter the water is liable to be affected by frost, which

Jnrovents the passage of the gas. If the waterlevelbetoo ow more gas will pass than can be registered, or if the meter be tilted forward the gas will pass without being registered at all, which, as may be supposed, causes much annoyance to the company. Why this form of meter should be used on the Continent in preference to the other I cannot say.—Harry G. Newton.

[4289.]—DANIELL'S BATTERY.—The fault " H. C. K." complains of is always experienced, and incapable of remedy without altering the battery altogether. I have been experimenting on this very subject for some time, and may soon have something to say on it. Probably "H. C. K.'s" battery has larger porous surface than is required for his work, and this may be corrected. Let him try with a galvanometer how much current passes through tho whole circuit and is just enough to do the work, and also when tho battery alone is in circuit; if the latter is more than double the former, he may diminish the porous surface by soaking and drying tho cells, and greasing or saturating with melted paraffin all but a portion facing the middle of the zinc plate. The point to be aimed at is to reduce endoamose to the utmost, and limit the action of tho porous partition to the exact quantity required for the current.—Sigma.

[4291.]—MAGNETIC BATTERY.—A number of bar or horse-shoe permanent magnets bound up in a bundle with their like poles together, so as to form a powerful compound magnet, is called a "magnetic buttery" or 41 magnetic magazine." Has " Beriro" been misled by the name? A •' magneto-electric machine," which is au apparatus for obtaining a current by means of permanent nnigncts, is a totally different thing, and depends upon the f;:ct that when a magnet approaches or recedes from it wire, a momentary current is induced in the wire. —Ignorant Irishman.

[4296.]—GALVANIC BATTERY.—" J. S.V question is inconsistent with electrical laws, and can only be answered if further particulars are given as to the conditions. If there is little external resintaneo or work to be done, the proportions of work can be seen at once by the figures given in my papers on each cell, as they were obtained by strictly jcomparablo cells. If there is any considerable external resistance or work a Since made of plates a yard square, would give less current than a Grove's lin. square. All depends on the relation between the electro-motive force and tho resistances, and thereforo each case must be considered on its own conditions. These points are little understood by amateur electricians, many of whom seem to think a galvanic battery has some magical properties, and therefore 1 will in an early paper lay out the whole system of the^laws which control the actions of galvanic currents. —sigma.

[4297.]-GALVANOMETERS.—I replied not long ago to this question. No galvanometer will give any very correct information on the subject, because the induced current is not a homogeneous stream, but a succession of independent pulsations in reverse directions. To use a galvanometer, it is necessary, therefore, to provide a commutator, which can separate the action at making contact from that which occurs at broaking contact, which, equal as to quantity, neutralize each other, though they arc unequal as tb tension. If the two ends of the secondary wire are led to the connections of a delicate galvanometer, and the primary connection with the batLery inaile by hand, at each make the needle will awing to one side, returning to zero, although the contact Ib sustained; mi breaking circuit the needle will swing to the other side and return to zero, and some estimate . may be formed ironi the extent of these swings, but to test the actual quantity some chemical reaction must be effected by aid of a commutator separating the two currents.—Sigma.

E4898.1— CHLORIDE OF SILVER.—Does "E. H." evaporate his chloride of silver in daylight '<• if so, this is the reason why it turns blue.—A. J. Jahman.

[4320.]—BREAM FISHING.—If "Pompey" wants to know the bent bait* for broain, I think I can help him. The tail of a lobworm used with the Nottingham tackle, is capital bait fin1 a river; but for a pond or stagnant water, gentles, with rather finer tackle and smaller hook will be found best. For ground-bait use worms encased in clay balls, or greavea previously boiled, either separate or mixed with bran or bread.—A. T., Staines.

[4328.]—MOUNTING MICROSCOPIC OBJECTS.— The method of mounting microscopic objects in Canada Balsam is to soak the object in liquor potassa for some time (varying with the opacity of the object], then to dry it between two slips of glass, soak it for a short time in spirits of turpentine, and place it in the balsam on the slide, apply a gentle heat, press the cover firmly on,

J ml- thu slide in the oven after raking out the fire, and ct it remain until the morning, when the hard Balsam can be scraped off, and the slide is ready for the cabinet. If " C. R. II." wishes to mount a cricket whole, ho will require to soak it, for a considerable time, in potass, until it is soft enough to allow it to be squeezed flat between two pieces of glass. It should then be soaked in turpentine, and mounted in balsam in tho usual way. Petals of flowers will not require any soaking, and the fresher they are, the better They are host mounted in glycerine, but if they are to be viewed as opaque objects, with the condenser, they had better be mounted dry. Mounting in glycerine is done tho same way as balsam, except that no heat is required, and that the cover will wai.t a ring of gold size painted round it, to hold it on. Dry mounting in the easiest of all. Merely place the object cm tie slide, put tho covor on dry, and paint a ring of gold size round it, and the thing is done. I hope *' C. K. H." will have better success next time.—Henry Sutton.

[4351.]—CONIC SECTIONS.—See Mr. Proctor's letter. [43H0.J—AQUARIUM.—The greenness of the water in an aquarium depends upon the amount of light admitted to it. The greenness consists of an immense number of microscopic plants produced from germs contained in the water, or supplied to it from the atmosphere. Strong bright light tends to develop these, hence tho thing complained of. The care consists in removing or

shadier place, or during tho hours when the light is most intense cover it with a sheet of light blue tissue paper, or the side next the light might have a sheet of the paper attached to it. At any rate the light must be lessened, then the greenness will gradually disappear. Tho best vegetation for an aquarium is tho green film which covers the stones or rockwork of either salt or fresh water aquariums. After they have been sometime in operation, these can be made to grow freely or otherwise, by the means indicated above. Pond, river, or marine plants of tho higher order seldom do any good. Exception must be taken, however, to Valisneria tpiralu, a. grass-like plant, which grows froelv in a fresh-water aquarium, is very ornamental, and gives out a good supplyof oxygen, which it is the office of these plants to produce. Further information if desired.—T. G.

[4380.]—AQUARIUM.—Scrub the sides with a toothbrush tied to a stick, and when the scum has settled put in a bent tube nearly touching the bottom (as a syphonj.suok out the air, and all the impurities will follow. Also keep up a supply of trumpet snails (Planarbis corneui and carinatwt), which feed on the confervoid growths. The fresh-water periwinkle, though ornamental, does not live long, and fouls the water fearfully when dead. Fresh-water mussels will also help to purify the bottom. For plants, the soldier plant (Stratiodes aloide*), with starwort floating on the top of tho water.— Amatece.



[4354.]—COPPER MEDAL.—Will any obliging correspondent translate the inscription on this copper medal, the head of which is very beautifully engraved, and tell me its probable value? Obv. Bust to right "CAROLVS XI. D.G., REX. SVECIAE." Under the bust " I.C.H." Rev. In ten lines, " 52 F. Nat. 1655, C. 1675. Reovperatis Provineiis Germ, ct Danis Extort a Pace Absolvtvm Imperivm in Regui Emolvni. Exergvit M. l(itJ7." Size rather larger than a penny.—Tatius.

[4355.]—"ART DEGREES" AND "MATRICULATION EXAMINATION."—It was with much disappointment that I read J. Harrison's answer (p. 357) to my query on "A. A. Degrees," as I am eighteen months in advance of the age he quoted, consequently I cannot compete. But if he will be kind enough to give me any in forma tu n as to the necessary requirements for the matriculation examination, or how to obtain such. I shall be extremely obliged to him; and whether there is any other degree that can be competed for, without matriculating; also the age. Or perhaps some other gentleman of the noble English Mechanic staff could give me the required information.—Bkiuro.

[4350.]—SOFTENING SKINS.—Can any of your numerous readers inform mo how to soften skins that have been cured with alum, arsenic, corrosive sublimate, Ac.? I want to make them pliable, so that they can bo stitched together, in order to convert them into » hearthrug ?—Countby Vet.

14357.]— COIL.—Can any one inform me how to make a good coil not longer than 1ft. Sin., to give spark in air lft. long, and whether I could use the same with a weak cell fur small experiments? and how many of the beat and what kind of cell it would require, how much wire, size of tinfoil, Ac, for tho Rhumkorff stylo, and what would the wire cost ?—A Youth.

[4358.]—COPAL VARNISH.—I have abont one gallon of good ci.mal varnish. It has been kept in a common can with wood ping for a year, and does not set under *U days. Can any one tell me how to make it set in about three-fourths of a day? An answer would much oblige.—A Youth.

[4359.]—AMBER BEADS.—How can amber beads be repolished, and what means are there to distinguish real amber from imitation ?—L.

[4360.]—GALVANIZING KAILS, Etc.—Will some brother reader plea-i? tell mo how to galvanize nails, &c, and whether there is not some other and better way to coat wrought-iron articles with tin, zinc, or copper without dipping them in molten spelter?—Makk Stewart.

[4861.3—METHYLATED SPIRIT.—Will any brother reader inform me what methylated spirit is made from, and why it is not allowed to be used in preparing tinctures?—Shellac.

[4362.]—CONDENSING WATER.—Will any reader give me a description of the machinery used, and the process of condensing water for domestic purposes on board large passenger-carrying sailing ships? If it is not asking too much, a drawing of the apparatus would much oblige.—Banchory.

[4863.]— LIMEWA8H ON MASONRY.—Can anyone tell me what will remove old limewash from masonry? I have a lot to remove, and don't know of any substance that will do it. Perhaps you or some of your'readers do. —Aoent.

[4364.]—DRYING SMALL WHEELS.—I am desirous of obtaining a quick and economical method for drying velocipede and other small wheels, not having the space or time to keep them as long as I should like before using them. Will somo kind brother reader assist?— S. W.

[4365.]-INDICATOR DIAGRAMS.—Will any engineering reader oblige by giving the best rule for calculating indicator diagrams to iind the horse-power of the steam engine? Also tho rule for finding the lap and lead of the slide-valve to cut the steam off at any part of the stroke that maybe desired? Perhaps T.J. O'Connor or J. Baskerville can assist me.—A Fireman.

[4366.]—INSECTS IN WATER.—I have a large iron tank (open to the air, painted inside;, which is supplied with water from two sources—rain-water, and water pumpod direct from a well through a refrigerator for cooling worts, the pipes being iron (whilst refrigerating. the water comes into the tank slightly heated). The uses I make of this water are to feed a boiling back, in which is placed a steam coil, with water to wash casks, &c. The other I use to feed my engine boiler. I find that n gieat number of little insects infest the water, which I cannot get rid of. Would any of vour numerous readers inform me of any substance which I could Lthrow into

out success. I also find that since I have JV engine boiler with water from this tank, I am obli clean the boiler every fortnight, instead of ovt-i months, when fed by the snine water from anothei ■ Could any of your readers inform me of any sub: > which would readily precipitate thomuddinesa i i tank without injuring the boiler or rendering tlae* unfit for cask-washing purposes ?—Copy Til

[4S07.]— RE-ENAMELLING ZiX&'t „,v

How can I re-varnish an old zinc clock dial
Sheffield Flood.

[4868.]— LINING-OUT SHAFTING.—Will your kind correspondents explain the usual n«-, lining-out shafting, say about 80 yards Iouk and ■ the pedestals for same ?—W. M. M.

[4S69.]-EMIGRATION.-WiU some of I have been discussing the emigration question kiibS* state whether it would bo advisable for a watch-iufcW to emigrate to Australia ?—Jobber, J-—^

[4870.]-PROBLEM.-8nppose a pole to be Iftfe* height; and standing perpendicularly, what part &'£■ pole will have to be cut off for it to touch the ei-4a, baso line 80ft. from the bottom of the pole which frar pendicular to tho base ?—Spn Beam.

[4371.J-CHANGE WHEELS.-Could our friend * Slater, or any of our cotton-spinning friends trivc a rir to find the change wheels for jack-lifter, cone 'and ratci-t wheels for roving frames ?—Good Words.

[43711-THE HAUTBOY.-Wanted, a few hint. *«•,, how to blow the hautboy, and tho kind of reed to strand what should be the cost of a good reed Ano's

[4373.}-TO -SIGMA.*'-Can "Sigma" 'explain ti* followfng?-The other day, as I was experimenting wui tho electroscope that he recommend-: on p ->Ti No -*'r Vol. X., I noticed a very curious thing. HavinofirK arranged the electroscope so that the pith ball hnV nearest to the stem, I hung a pith ball on bv n lin^ thread, and took off Lhc gutta-percha bull on the othrend of tho wire. I then excited a* of ffutta-wrSii with a dry silk handkerchief, and applied a proof phm.

1 touched the plane and then withdrt'

and approached it to the other end of the wire* on w?n>h the pith ball hung, in fact to the place where 'the indiarubber ball was ; as soon as it pRnie near the ball receded from the stem, and receded «,= the proof plane approached tho wire, until it came near enough to spark. If this is repeated once or twice the ball aoe<t further away than it did the J3r**t time, bat after that it will go no further. I also noticed (hat while the ball under tho influence of the electricity in repelled from the stem, if the proof plane be approached to it it is repelled until it gets close to it. when it is attracted. Such was the result M mv observations, which I was at a loss to understand, but 1 \iav* n..» doubt that you can explain them satisfactorily. M*o c*a youtett me where to get the green carboy*, in London that 1 have often seen recommended in these pfa**. * tor making the cylinder

electrical machines, and also the coat ot them"?


4:4374.]—PRINTING.—Would some one inform me of a way to transfer ready printed mutter to zinc plate?, to as to be able to take impressions from them?— Cutiibert.

[4375.1— RED BRONZING.—I should feci obliged if any subscriber would tell me how the red bronzing L-o chandeliers, gas brackets, &c„ is done, i I understand the green bronzing and lacquering, but not the red.—


[4376.1—COD LIVEK OIL.—Can you or any brota«r

reader tell me of a substitute for cod liver oil? I ha-nj been frequently advised to take it (being of a weak constitution), but I cannot master U; the sight of it btiac often too much for me. I would ho glad if tavoBo could tell me.of anything more palatable, and a**xW.— A Mechanic.

[4377.1 — TEMPERING BRACE-BITS.—Will as? reader of the English Mechanic inform me bovtctt harden a set of iwlUhod brace-bits, mine heing ail i** soft? They ought to have been good, as they cost £i fe. —A Mechanic.

[4378.]— HOW LL.D.'sARE MADE.—I see you allude in a somewhat satirical way in your last number to u Doctor " Bedford. I don't know whether he is a D.CX, LL.D., or M.D., or what besider. I see two Lutdon gentlemen have recently been putting LL.D. aftrtheir names, or others have been doing it for them- I allude to J. Baxter LaTigley, LL.D., and W. C. Eenm-i LL.D. Now Mr. or rather Dr. Largley as the rrewdo of tho Sunday League I know, and I have heard of ** Bennett, but not as a Doctor. For what I know to • contrary, these gentlemen may have honorablv •* their degrees. But I should like to know a little'sff* the modus operandi. I know a smattering of Latin.* read French, am pretty well up in mathematics t*~ graphy, and music; and I should like to be tin lU'Will some one enlighten mo as to tho how and tae «pense?—An Ambitious One.

[4379.]—BORING CYLINDERS FOR MODEL T^GINES.—Will any kind correspondent tell rue bow to bore the steam ports and channels in a model enjrim- * I have a solid casting, and, although I can manage U> bore the cylinder itself, I want to know how I am to srt about making the channels which admit tho steam to the ton and bottom of the piston? I have not any tool?, and I know nothing about the work.—Sabiias.

[4380.1—COLZA OIL.—What is the oil known by the name of colza made from? Is there anything peculiar in the process V—Sambas.

f4881.1—COURT PLASTER.—How is this made; and why is it called "court" ?—Sabbas.

[4882.1— COPPER COINS.—Can anv brother reader of our valuablo paper inform ine what the following coins are? 1. Obverse : Bust to right, " Diva Faustina^.** R<»_ verse: Female standing beside an altar on a tripod "Augusta S. C."—2. Obverse: Bust to right; "Imp* Caes. . . . an Aug. . . M E O XL" Reverse: A temple between "S. C," "Aug." below. They are

copper, and very thick, about the sise of a penny.


[4383.]— THREE COINS.—I should feel obliged if yoa could spare me a corner in tho English Mechanic forthe three coins enclosed, and perhaps Mr. Henfrey, ox*

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