Abbildungen der Seite
PDF
EPUB

Thus chemistry shows us that mighty and vain man
has not much to boast of. His insignificance becomes
apparent when we reflect that water constitutes three-
fourths of his body, and that of the 431b. of solid mate-
rials that build up the human fabric, most are uni-
versally diffused throughout creation. A lesson of hu-
mility ought indeed to be learnt from the inspired
words "Dust thou art, and unto dust thou shalt return."
During life a constant destruction, a never-ceasing
From
waste of all parts of the body is taking place.
the first moment of our existence to the last day of our

[blocks in formation]

FISHING RODS AND TACKLE. [150] SIR,-Noticing some enquiries in your journal tion of tyros in the sport of angling, a few necessaries,

gut for casting lines may be bought in hanks, and it is cheaper to do this and make the casts oneself-joining the threads by a water knot, which any angler can ex plain. Now, armed with the above necessaries fly-book, a pair of scissors, a baiting need gorger, some spare gimp and gut traces, and au ment of Limerick hooks, a live-bait kettle, a bag worms, some split swan drops, and one or two enla floats, the angler may go to any river or lake u world and get good sport. He may entice the trout, the beautiful char, the elegant grayling, the sa white trout, the timid chub, the lazy bream, the gat

lives these incessant changes are never for a single lately, relative to the above, I jot down, for the informa- pike, the monstrous salmon, the slippery eel, the s

moment suspended. We cannot wink an eye, move a

finger, see an object, hear a sound, or indulge in a thought the possession and the proper use of which will enable roach, the lively bleak, the handsome perch, the without a certain portion of our substance being sacri- any of them to get good sport wherever tish are to be flavoured tench; with the carp, the barbel, and t siologists calenlate that a quantity of material equal to general rod-no doubt it saves trouble in carrying-fishing this year has been particularly good everywher

ticed. In fact, so rapid is the wear and tear, that phy

one.

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 our old body and have a new This constant waste, 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 First the fat disappears, then starvation would ensue. the muscles shrink, soften, and decay; next the brain the series of events. It is by the agency of our daily becomes attacked, and delirium and death complete Now it has been food that these losses are repaired. "contained in the human found that the "principles body also exist more or less in our various articles of diet, hence it is easy to understand how readily food becomes "assimilated" or converted into the substance of the body, thereby fulfilling the conditions most conBETA. ducive to our health and happiness.

[ocr errors]

THE GUN, THE BALL, AND THE EARTH. [148] SIR,-He is a bold man who takes up the cudgels with such an opponent as "F.R.A.S." And, but for his invariable courtesy, I am not sure that I should do so. In reference to "Curious Question (p. 378), the gun, the ball, and the earth are all travelling eastwards at 1,000 miles an hour on a circle of 4,000 miles radius. If sufficient powder and elevation be given to keep the ball in the air for ten seconds, and therefore to send it to a height of 5,456ft., or a little more than a mile (we may take the ball to be 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 an 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 for nine seconds. The sum therefore stands :

Hour. Seconds. Mile.

Yard.

1 : 9 :: 1 : 1.1 an amount of "westing" invariable, whether the gun be fired perpendicular or at any angle, N., E., S., or W.

The theory of projectiles in high latitudes is more complicated. T. S. USBORNE.

IRON IN BATTERIES.

[149] SIR, A maxim I strongly hold to and deavour to practise is to learn something every day, so that I am always ready to modify any opinion what ever, if further experiment or thought shows that it is right to do so, 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.

found. Few anglers care to have what is called a 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 emergenTherefore, I would cies occur so often as in angling. always recommend anyone wishing to become an angler to have a rod that suits the fishing he is desir ous 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 be using. I small tront with a single-handed light fly rod and have known a first rate fly-fisher, when whipping for n fine line, hook a large salmon, and land him safely. For a trout stream, at widest part not more than 18ft., light single-handed rod of 11ft. or a few inches more or less is just the thing. This may be made in three 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; the second or middle piece made of hickory, and the top made of lancewood, finished off with about 16in. 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

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

A salmon rod should be 18ft. 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 brass 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 be done with a piece of well-waxed end.

A reel for a single fly rod should hold about 30 yards of fine line, made from silk and hair. The 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, best 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.

gudgeon, nay, even the tiny stickleback itself. Th and there is no sport so enjoyable as a day's good t ing-wandering along the mossy banks, inhaling a clear balmy air-far from smoke and dust and cae ! may shortly, with your leave, give a list of acces for sea fishing. VIVIS SPERANER

PRESERVING FRUIT, ETC. [151] SIR,-Would any one of our many readers t know how, or has himself preserved fruit, kindly raks known through our journal the modus operandi) I particular point on which I wish for information is the tin cases which generally come from America, cer taining peaches, are hermetically sealed. I wished to preserve strawberries in this way, and so I filled a tin ca with them, putting in a little sugar and two or thre spoonfuls of water. I then soldered on the top, leaving. of course, a small hole. I put the case then on a c fire, in order to get the case filled with steam, wh when I felt it boil, I took off, and sealed with a drops solder the small hole.

If I thought this was the right method, I world make up some more; but to find when I came to open them that all were spoiled would be rather disay pointing.

Did I do wrong in putting any sugar in? I conll not get the steam to come out of the small hole in a jet so that I could see it, unless when I shook the case. I was afraid to boil it long, i.e., more than ten minutes, for fear of softening the fruit.

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

[blocks in formation]
[blocks in formation]

change of the sails from the horizontal to the vertal very severe unless he can break its fare f interposition of a spring. I mean to compare them as to the amount of power given off for the same At present, I think the "Rustie's the most powerful form of sail; but this is more than counterbalanced by the jerking motion, the difficulty of properly fixing the pulleys over which the rope jaizi, the opposite sails passes, and by the severity of strain which the arms are required to bear.

position is
It is dreadfully provoking to lose a
fine fish through the breaking of a rotten line. Very
hard-twisted lines, although they look smooth and
strong, are apt to be brittle, owing to the hard twisting
en-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 cared 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 the floor, or coiling them
round the backs of two chairs. The joints for rods I
recommend to be tongue and socket joints, with a brass
bent pin attached to each piece near the joining,
around which a strong silk or linen thread may
lapped to prevent the joints separating when the rod is
in use.

I have very strongly condemned iron as a negative metal-that is, its use in place of platinum and carbon in nit ic acid and other batteries, but in the case in question it is to be used as the positive in place of zine, 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 the calculation (p. 387), it will be seen that the cost of the zine is only about one-fourth the total, reckoning it at 7d. per pound, double what it may readily be got for, as I buy it at 34d. If we reckon the iron at 1d. only, the difference of cost will not be a very large proportion of the whole, while the current would be considerably reduced in force, and thus it becomes very doubtful

economy.

fetid unwholesome gas given off, owing to the carbon In simple acid cells a very serious objection is the 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 the proportion of gases given off or absorbed depends greatly on the rate of action. On short circuit, as when I tried it, the 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 in the action of the Grove's cell is not a ferrocyanuret, as Mr. Haines suggests, because it is produced in the absence of iron; it is considered to be due to the solubility in the nitric acid of the lower oxides of nitrogen produced, and which when the acid is saturated are given off as 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.

be

The flies next demand our attention, and here let me say, that it is quite a mistake to have a large 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 flies, which may be the means of filling a basket sooner, but in the hands of an expert angler the few standard flies I here enumerate will do all that is wanted-give sport, and fill the creel-and can be Lug, March Brown, Red and Black Hackles, Blue Dun, had at a moment's notice at any tackle shop. Hares Wren Hackle, Gronse Hackle, Partridge Wing, Green Drake or May Fly, Grey Drake, and the Francis Fly. Salmon flies have different names in different localities the Butcher, the Doctor, the Professor-all sorts, 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. artificial. I could not enter upon the manner of hookThe baits for trolling are very numerous-both live and ing live or dead bait in the limits of this letter. Artificial minnows do very well, especially for the Salmo ferox. The spoon bait or archimedian spinner 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 6ft. long; the casting lines for trout should be of fine gut, and may be only 3ft. 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

Another disadvantage is that the whole power is e erted on one side of the mill, whereas in the Va construction the sails on both sides of the mill may act at the same time, and thus this form approaches ne nearly to the vertical mill.

the one he describes on page 40 in actual work. > Has H. W. Reveley ever seen a horizontal mïb proportions he gives seem very large for so little He seems to be mistaken about the open her sails, as he says "the wind only catches one saldrá time, and that only for an instant, besides the inqu difficulty of getting the sail frames back a wind." What does he mean? there is no in

t

difficulty. In all forms the sails come back edge to the wind. There is no such great di the air, and that is all that the edge of free sto the vertical, for then, too, the edge has to DRLİ Reveley's part would have shown him that this do in the horizontal, and a little consideration e. for though he may say one sail has to come up wi edge against the wind, and so cause more resistance t the edge of the vertical moving in what may be sail moving with its edge with the wind, so that the garded as still air, still, he must not forget tra balance this resistance there is on the opposite an. sistance from this cause is reduced to nothing. I should like much to see some more disenssion. Vallance, no one who has written has stated that the horizontal windmill. With the exception of 3 mill did any real practical work. "Rustic from fieshire has not fulfilled his promise to send drawin~? therefore, any further information as to practical wers his more powerful mill, which he speaks of in hisle? on page 18 of this volume. I mean to make a mill, a ing would be most acceptable. already given me much help, and I think the subje of a cheap motive power is well worthy of a place

[ocr errors][merged small][merged small][merged small][merged small]

15

4

and not at 3h. 52m. in the afternoon of the 24th. Mercury
s not in superior conjunction with the sun on the 28th,
e is in conjunction with that luminary on the 27th at
b. 20m. a.m.
Why has "F.R.A.S." discontinued to give us the
Eme of rising or setting of some of the planets ?
It must be acknowledged by all, that it is far more
onsonant with reason to give us the right ascension
nd declination of the sun, or the longitude in the
cliptic, than to state that his right ascension is (on the
st July, 1870) 6h. 40m. 50-48s., and his declination 23°
22.7 N., and that he is "consequently" in Gemini,
c. The inference or deduction is illogical.
Why do the compilers of the "Nautical Almanac"
reckon from that important point called the first point of
r? You have his right ascension compated from this
point, as well as his longitude, &c.

The Firth point of view" is therefore, as you are pleased jocosely to term it, of far greater importance han the outlines of a fabulous animal. In short, we refer to say that the sun is in (the sign), and not n (the constellation) II.

G. FIRTH.

GEOMETRICAL APPROXIMATIONS.

use.

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 in shape should be used for this purpose. The handles should be long and the inside of the mould should be well blacked over the gas. Before casting, the mould should be made so hot that it will not admit of being touched by the hand.

the weight of air at 14oz. for each cubic foot, it would
require about 1,970 cubic feet to be displaced to raise
11 stone weight (i.e., 154lb.). Pure hydrogen gas is 14
times lighter than air. You would require about 140
cubic feet of this gas, but common carburetted or coal
gas is generally employed, whose density is rather more
than half that of air. Using this would require about
1,000ft. To this must be added the weight of balloon,
car, and cords.-PATIENCE AND PERSEVERANCE.
[2677.]-HYDROGEN GAS FOR BALLOON.-" Henry
Nutt" does not state which carburetted hydrogen gas he
how high he wishes his balloon to rise, nor what is its
intends to use, whether CH 4 or 2 H 4; nor does he say
weight.-R. T.

[2677.]-HYDROGEN GAS FOR BALLOON.-Taking

suggestions for models of harmoniums. I have some 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. 399) to "J. C. P.," and as the result of my experience I said that there are no makers of large harmoniums amongst them; no oneWALTER J. NICHOLLS. who attempts to introduce a novelty either in tone or in expression; every one working on the same model, and one, indeed, I met who would rather not hear of anything new or different, and certainly would not work to originate anything. Nearly dispirited, I took heart from reading the advertised testimonial of Dr. Leslie in favour of the Professional and Connoisseur's Harmonium to see the harmonium he praises. In addition to seeing it I had the good fortune to see an extraordinary harmonium the same maker is exhibiting which surpasses anything I have 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 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 [154] SIR, I herein enclose some of my geometri- delicious notes, so soft it is an echo, not by a breath al approximations inserted in the Philosophical Maga- resembling reeds. I cannot understand it, but I am ine, stimulated by Mr. Proctor's in your number charmed to find that anything can give sounds so of the 8th inst., page 376, his L G being simply one- gentle without any difference in blowing. By one stop ifth of 2-0 B or O G, producing 3-141421. The making a wave of sound dreamy and delicious in its there is a very pretty beat in the note, quite a pulse, ate Mr. Willich gave, in his Popular Tables," a nearer ebb and flow. I cannot take the bass part for reeds; it approach, and were my numerical triangulet convert-is deceptive enough to pass for wood pipes, though in ble to a geometrical appendage it would be very close. the bottom row of keys there is something quite difYou perceive I found, from considering 3150000 ferent, and more like an harmonium. I should be glad 34000=735 that (3000000-8007 =A) 21 gives 314159215 to describe to your readers its effects. I have nearly got what I desired as to loudness and boldness. My old and affixing (12002) A, or 35897932014, we have words "rank and strident," though not strictly applictrue to 16 decimals. The first portion is representable able here, picture a want felt by all musical natures. by tracing a semicircle, diameter 1000, applying Light and shade are required in musical scene painting as well as in nature. I much want a trumpet stop in 3007 an harmonium, but I am informed I cannot get it. Next best to it, I find in the lower row of keys stops of These taken in comgreat brilliancy and power. parison 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 flute and clarionette. The contra bassa is a power by itself unique. They are not unaptly described by Dr. Leslie, whose 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 the other knee swell, and it pro

20

√503 + 182 = 1. 3007 as a chord, and reducing the

5

3

7

supplementary chord in the ratio of the ordinates to the alscisse of and of the diameter, producing a chord exactly equal to V314159265.

[ocr errors]

Page 374.-Although as an old Fellow of the Royal Astronomical Society, I rejoice at the further extension of the "family likeness" 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 and sentient beings, knowing as we do the immense terrestrial va-duces an effect of piano, either on one stop or on full riety God has formed out of the few chemical elements, oxygen, hydrogen, azote, and carbon?

Page 380.-Metrical Act: Referring to the "Companion of the Almanac " for 1827, page 100, I lately deduced that (883 000536) pendulum lengths 960 yards per Act of 1824.

=

power. I may say I have found in reality twenty-seven
stops and nine sets of reeds, whilst your correspondent
has been playfully poking his fun at me respecting his
harmonium of the future. Thanks, however, to him
for his kindly notice of me as regards the sketch of the
piano.
ALEXANDRA.

P.S.-I see that some other correspondent has
the nom de plume under which I address yon. Would
you kindly desire him to adopt some distinguishing
addition, or to substitute a name not already appro-
priated. This I ask in order to prevent confusion.

Univ." t. i. p. 194, says, speaking of Egypt," the dogmas
[2694.]-GREATER PTHAH.-César Cantu "Hist.
particular to the priests acknowledge a unique
Supreme Being, who could not be represented by
corporal images. Plutarch says their highest science
consisted in regarding Phta as the great architect of the
universe; they worshipped specially his wisdom at
Sais under the name of Neit, his goodness at Elephan-
serpent rolled upon itself."-BERNARDIN.
tine, under that of Cnef, the symbol of which was a

[2756.]-LAMENESS IN HORSES.-In the first place, fryn's" query sooner, but through pressure of business, I must apologize for not having answered "J. O. Dufand 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 depletive measures, viz.:-Physic ball, composed of Aloes Barb. 6oz.; bleeding at the jugu ing diet, rest, &c. On the other hand, if the disease has lar vein; bran or cow-dung poultices to the feet; coolassumed a chronic form, which it generally does, I know of no better treatment than the adoption of Mr. Broad's heavy shoe, invented especially for laminitis, or fever in the feet (of which I forward a sketch), which has lately

A

made its appearance before the public, and has elicited such a lengthy discussion in the pages of the Veterinarian, Field, &c. From my own observations, and that shoe extant. Should the querist require any more information, I shall be most happy to render it.-COUNTRY VET.

In the Philosophical Magazine for January, 1841, I attempted to show that the equatorial circle plane of a rotating orb whose 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 where these forces balance each other, and a molecule there will be undecided to revolve round or fall upon the orb. It is curious that Kepley's law applied to Mercury and the solar limits, to our moon, and 3/289 to Jupiter's EXTRACTS FROM CORRESPONDENCE. of others, I have come to the conclusion that it is the best moon and his limit, give from the secondaries' period the rotation times of the orbs Virg. 60: 289 :: (27 days 7 hours) ... (24 hours) } 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 hours with his moon's 42 hours, and perhaps thus indicating the limit sphere separating the primary local influence from its action as a cosmic body S. M. DRACH.

on the others.

THE MONSTER HARMONIUM OF THE FUTURE.
[156] SIR,-The Tantalus cup held to my lips by
your correspondent" W. T.," No. 257, page 580 (whose
initials you printed "R. T.," which will account to
"Harmonious Blacksmith" for my addressing him
under those initials), has never been removed. I sus-
pected he was quizzing in proposing the scheme of an
harmonium with 19 rows of reeds distributed between
two manuals, and 3 rows extra allotted to the pedals:
and I prayed him in my letter (No. 260, page 657), as
an earnest enquirer after the most perfect harmonium
that can be suggested, to afford me, if he was not
quizzing, certain information, which, although then it
was March, and now it is July, and our journal has
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 unap-
peased. Despairing of a satisfactory reply, I have been
compelled to treat the whole description as a joke;
otherwise, I should have been very glad to have given
an order. These sort of jeur d'esprit may serve as a
little amusement amongst weightier matters, for
seekers after lighter literature than the staple of our
journal, but answer no practical object for earnest
enquirers.
Another thing, waiting these four months has left
time to look around and examine various models and

[blocks in formation]

1 18000

TRACTION.-"J. B." says:-"In reply to Mr. Thomas, page 394, the 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 this, which is effected by the tramway, is, of course, therefore, as beneficial on a gradient as 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 rails. It, therefore, is far easier 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 the wheels should be chocked if the horses are stopped, as the tendency to run backwards is as much increased by the tram as the upward draught is lessened by it."

REPLIES TO QUERIES.

[2666.]-COPPER DEPOSIT ON CAST IRON.-Watts's
coating iron with copper:-Carbonate of potassa, 4oz.;
"Electro Metallurgy," gives the following solution for
sulphate of copper, 2oz.; liquid ammonia, about 20z.;
cyanide of potassium, 6oz.; water, about 1 gallon.
Dissolve the sulphate of copper in boiling, distilled, or
rain water, and when cold, add the carbonate of potassa
and ammonia; the precipitate, when formed, is re-dis-
solved. Now add the cyanide of potassium until all
the blue colour disappears.
at the bottom of the vessel, from which the clear solution
A precipitate will be found
may be decanted. Two cells of a battery will be neces-
sary to deposit from this solution. Articles of iron
which are to receive this deposit should be previously
soaked in a strong solution of caustic alkali, either soda
or potassa, made by adding to either of these salts some
recently slaked lime; the clear liquor proceeding from
which is to be used for the purpose of removing any
grease which may attach to the article, which is to be
then well washed and immersed in a pickle consisting of
inch sulphuric acid, 1lb.; hydrochloric acid, 2oz.; water,
14 gallons. After the iron has remained in this pickle
for a short time it may be removed, and well washed and

[3703.]-PASTEBOARD.-Thomas Grist should put his pasteboards into an hydraulic press. They will be quite straight when dry.-ŠAUL RYMEA.

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

[3726.]-CHROME BLACK.-I beg 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, and boil them well for half an hour in clean water and argol, take them up and hang them up to cool, throw away the contents of the copper, fill it up with clean water, make it boil, and put 4oz. of chrome and 4oz. crude tartar in the copper. Put in the goods and boil well for 40 minutes, take it up, cool it, throw away the contents of the copper, and fill it up with clean water, make it boil; put in as much logwood chips by weight as the goods weighed when dry, and a quarter as much fustic chips, boil well for 10 minutes; while this last copper is getting on the 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, cool, rinse, dry, and they are done. He says the argol copper, making two coppers do the work. The some dyers clean with chamber-lye, and dispense with 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.

[3752.]-DEPOSIT FROM SODA CRYSTALS.-In deposit that he complains about is soda. It is caused by reply to the query of "Natrum" on this subject, the the solution being too concentrated to retain it in solution, and by the heat. To prevent it getting into cakes it must be stirred continually, and especially at that part of the pan which is exposed to the greatest heat. Does "Natrum" 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 he does? Then during the evaporation the 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 scale, is still in want

of the same information, I shall be happy to furnish him with the same through the medium of the ENGLISH MECHANIC.-JOSEPH ROSKELL.

[3798.]-BAROMETER TUBES.-A little strong acid will remove every film and make them fit for use.WALTER J. NICHOLLS.

[3766.] -CLEANING AND REFILLING BAROMETER.—Lardner's" Museum of Science," No. 44, says: -When the mercury has been purified it is next necessary to render the tube perfectly clean on its inner surface. It generally happens that tubes exposed to the air, always more or less 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 10in. 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 heat escapes from the tube. Mercury is again introduced, and again treated in the same manner, until the tube is filled. In this process it is usual to heat the mercury to nearly the same as that of the tube before pouring it in, otherwise the difference of temperature might crack the tube. When the tube is completely filled the open end is finally stopped with the finger, and being inverted, is plunged into the small cistern of mercury at bottom of barometer. -PATIENCE AND PERSEVERANCE.

-The

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 see the grease begin to show a blue flame roll them in water, and your springs are tempered.-Deeside.

soap. I find no fault with "Saddler's" method of treat
ing harness; but think the oil would be better applied
before it was quite dry. Couriers lay on the oil when
the leather is wet.-BANTING.

A ca

size of the chamber and number of stills must be accord

[ocr errors]

all. The pure article is the carbonate of the metal, and its commercial value in the dry state averages from 304. to 36s. per cwt. The adulteration of white lead, on account of its high specific gravity, would have beg [3875.]-BLEACHING POWDER.-In reply to " Gra- rather difficult were it not for the existence of a cert tus" the following is the method of manufacturing mineral nearly corresponding with it in this res bleaching powder:-The lime used for the preparation and of very little use in the arts otherwise. This te of this article must be of the first quality, for unless sulphate of barytes, a ponderous, massive, tram this is attended to the salt prepared from it will be very volcanic rocks. Two important veins of this des mineral, occurring in extensive veins, permeating e interior in colour. To prepare the lime for the absorption occur in Scotland-one in the island of Arran, F tion of the chlorine gas it is brought to the screening department and slaked with just sufficient water as will of Clyde, the other at Muirshields, in Ayrshire-b which are worked mainly for the purpose of adul cause the lime to crumble into a very fine powder; some care must be taken that not too much water is used, or it ing white lead. A few years ago, I carefully examiast will be difficult to screen it. The powdered lime is then the workings of the vein, and also the process of m screened or sifted through fine wire gauze sieves, hav- facture of the adulterant at Muirshields, which have bee ing about 400 apertures per square inch. The next step cal, having an inclination of probably 5 or 7, in progress for many years. The vein is almost re to be considered is the preparation of the chlorine gas. This is obtained by acting upon peroxide of manganese upper edge cropping out on the surface in a peristy with hydrochloric or muriatic acid. The stills used for moorland and mossy district. The gradual progres, a generating this gas are formed of large stone slabs, the removal of the barytes has left a considerable grooved and well cemented together, and in the form of behind the actual operations, from which I ascerta a cistern; this is again surrounded by a casing of fireas nearly as I can recollect, that the vein varia thickness from 1ft. to 5ft. The direction of the bricks, iron, or stone slabs similar to the others. vity of about 6in. must be left all round between the two; this serves as a steam chamber, and is used to heat the contents of the still. The size of the still outside, including the steam chamber, may be about 9ft. square and about 4.t. deep. Inside of the still, and supported on pillars about lit. above the bottom, is another stone slab called a table; on this table is placed the manga[3781.]-PHOTOGRAPHY.-I once used the wax paper nese which is to furnish the chlorine gas. From the process, and to change the paper made a bag of three stills the gas is conveyed to the chamber through earth folds of black calico one side, and three folds of yellow enware pipes; the joints of these pipes are connected the other. There were two short sleeves about one-third together by water lutes, so that no gas can escape. from the bottom of the bag with elastic wristbands, and Various apertures are required in the top of the stills, a the top had a hem with running tape. I put "back" large one in the centre for charging the still; other and portfolio into the bag, also my head and pulled the small ones for running in the acid, and another at one tape; then put my hands into the sleeves, made the of the sides and at the bottom for running off the waste change and then reversed the process. The only objec-acid before recharging. This last is a round hole, and is tion to this is a frolicsome companion'-M. W. G. stopped with a wooden plug. The chamber is formed of lead, supported by a framework of wood, similar to a [3787.] TEMPERING BUFFER SPRINGS. vitriol chamber. The chamber has two doors, which bottom of the chambers are formed of fire-bricks. The are luted close during the time the charge is in. The ing to the quantity of bleaching powder to be made; the height of the chamber must be about Gft. Having now briefly described the apparatus and the use of them, I will proceed with the manufacturing process. The first step consists in charging the chainber with the powdered lime to a uniform depth of from 4in. to 6in.; after this is done the doors are 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 3in. or so above the 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 heat the contents. In a short time the gas begins to evolve, and passes through the pipes into the chamber. The charges are 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 in. During the time that clapses 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 the contents with short rakes, until 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 36 to 37 per cent. of culo rine. The time occupied in doing this depends on, first, the quantity of lime placed in the chamber, because the thinner the layer of lime is the sooner it will be complete; and, secondly, the quantity of gas passed into the chamber, but perhaps four days may be the average time in preparing it. When thoroughly impregnated, and if the still is not worked off, the gas from it is turned into another chamber, the chamber doors are then opened, and, as soon as it is convenient to enter, the lime is packed in casks. I hope this information will be of use to "Gratus."-JOSEPH ROSKELL. [3888.]-ALARUM FOR DUTCH CLOCK.-If "Amamaker, and examine a Dutch alarum clock, he will learn which would be practically useless without figures. more in ten minutes than he would from any description, -R. T.

[3789.]-AVIARY.-Having just completed one for some 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 3lb. of 16 tinned wire, 21b. of 12 ditto, and lb. of binding wire; bored the holes in. apart for the small wire, and 3in. apart for the cross wires,using a bell-hanger's small pliers to cut the wire into lengths. Some difficulty will be experienced in straightening 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 PERSE

VERANCE.

[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 found the boots (2 years old) to be 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 the benefit of "Old Scrub," or any other man, I give the recipe. 2oz. best white wax, oz. prussian blue, 14oz. 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 4lb. 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.teur Horologist" will pay a visit to any country clock

LEATHER.

[3831.]-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. Trübner & Co.'s, German booksellers, London. -BERNARDIN.

[3841.]-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 trapezina is greenish, with the dorsal, subdorsal, and spiracular lines white; the spots are black or dark green. It is full fed at the end of May or beginning of June. It is a noted cannibal. It feeds on oak and birch, between a packet of leaves united with silk. —R. T.

[3851.]-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" the 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, &c., and that after a saddle has been out of use for some 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 is not all made of hogskin-instance the parts above named, and I have seen saddles look a better colour and keep in better condition with the application of milk than with soft

[blocks in formation]

[3926.]-FORCING WATER.-" B. S. 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. In his own case the lengthening of the pipe would be an actual disadvantage, as the fric tion of the water-flow in the pipe would be multiplied six-fold.-MATRIX.

[3934.]-ORGAN ACCORDION STAND.-If "Sigmatau" will look in No. 158, page 516, he will find 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 be to grind it with oil between the stones of the under one large. To apply an alkali, in order to disa regular paint mill, or by hand between two flat stones, solve out the highly oxidized oil, would inevitably destroy the article as a paint.-MATRIX.

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

dyke, as it may be called, extends nearly east and
crossing the Frith in the direction of Arran; ante
can scarcely be a doubt that in the dim vistas
past, long ere Time's erosive tooth had gnawed on the
deep and tortuous channels, the far-reaching rock an
craggy, savage glens, the endless succession of heather
clad mountains, and the lovely isles which a
up the matchless scenery of our lovely Clyde, th
barytic rock formed
fragmentary seams of
grand dyke, on the extent of which it would be
less to speculate. Barytes thus found is generally e
or more discoloured by streaks or blotches, FL
mainly to the presence of oxide of iron. The miner
after being deposited at the works, is crushed to a far
powder by means of ponderous iron rollers, revolva
with their edge resting in a large circular iron pe
similar to the arrangement employed for the grinding
loam in a foundry. After having been thoroughly gro
the mineral is digested in very dilute sulphuric acid,
digestion can be repeated with frequent stirrings arti
rather in water strongly acidulated by that acid in taa
or vats, which should be lined with sheet lead. Th
the bleaching is completed, and all trace of the act
after settlement. The pure barytes thus obtained a
can be removed by repeated washings and decantatia
now thoroughly dried in any convenient manner, and
in this condition is ready for market. It now only
remains to be told that the manufacturers' white lead
of commerce is made up by mixing the two ingredients
buyer, or the conscience of the dealer, those proportions
in very various proportions to suit the pocket of the
varying from probably 75 per cent. to almost zero of the
other. I need not explain that all this is performed in
genuine article to the corresponding complement of the
the ordinary paint mill with a sufficient admixture of
oil. Taking the value of pure white lead at 55s. per cwt.
and that of barytes at £3 per ton, the margin for profit
resembles, in a remarkable degree, white lead, yet,
will be at once recognized. Now, although barytes
being essentially crystalline in character, and hence
translucent to a certain degree, it does not, as a paint,
kindly a manuer with the oil as the more flocculent lead
cover so well, nor yet does it mix or combine in so
So that "H." should not be surprised if his lead bas
split partnership with the oil and become a solid
mass. I have already said that this barytes has
specific gravity alone being often taken advantage of
few applications except as an adulterant; its high
under circumstances which would scarcely be anti-
cipated. I will just refer to one instance for the benefit
of our "Harmonious Cotton Spinner" (I think we have
placing on the spindles of spinning mules, and which
one) and his congeners. The little paper tubes used for
receive the first windings of the yarn, forming in t
the bottom of the cop, are made by rolling upon a
sheets of paper pasted on one side, drawn off the wire,
in this little process is amply charged with baryte
dried and cut into suitable lengths. Now the paa d
spinner, although in the first instance defrauded by the
tube maker, has good reason to wink at the dece
as he, in turn, disposing of the tubes along with t
the extent of the difference.
yarns, at maybe some shillings per pound, benefisi
The mineral barytesi
compound of the metal barium, oxygen, and sulp
acid. By mixing it in powder with charcoal, and e
jecting it for a time (in a crucible) to the heat of: 7
nace, it becomes reduced to the sulphuret of ba
having lost its oxygen. In this condition it is st
barytes, a salt used by the pyrotechnist in the pr
acted on by nitric acid, for the formation of nitre!
tion of green fires. This fact will point out to "H"?
he possesses one, a ready means of testing the presTICS
of barytes in his white lead by means of the pij®,
as a small piece exposed to the flame would gr the
characteristic green flame similar to that oppez
or still nearer to that of iron, but not -
ALEXANDRA.

[8990.]-YELLOW DYE.-"A Countryman"
lamine yellow, to be obtained of most chemists and dry-
try Manchester yellow, otherwise known as Nea

salters.-SAUL RYMEA.

[4010.]-MELTING AND CASTING METALBristol Amateur" should get some metal from a ste typer's. As a rule, it is slightly harder than type which is made of three-parts of lead and one of anti ordinary type-metal, till he gets the cast as hard as? Failing to obtain this he must add bismuth to wants it. The metal must be perfectly fluid, so run easily into all the crevices of the designs; be obtain a thoroughly sharp cast a proper casting** must be made. This may be either made to dip** the molten fluid or be so constructed that the fluid be poured in. It consists of an iron tray made with closely-fitting lid kept in position by a screw, and have the corners cut off to act as inlet holes. Into this in the design should be placed "face" downwards; t lid screwed down so as to leave the required space! thickness of casting; and the casting-box in serted i direction to allow the air to escape at the upper corn the molten metal, which should be done in a diago The other method consists in having a thick iron b with one end open, made to unclose longitudinally, s which it is designed. The mould is then fastened on leaving space according to the thickness of the cast! side of this, the box firmly closed, and placed in

rtical position, and the metal poured in between the and expense to him to do it himself, and would cost to slabs forming the box.-SAUL RYMEA.

(4143.]-POTTERY.-In baking china and other pottery trials" (made of clay specially prepared for this purse), are placed in different parts of the "kiln," these trials change in colour according to the heat of the In, the "trials" are drawn out with a long iron rod aring the baking, and when one of the desired colour is rawn, the "kiln" has the required heat and the goods re properly baked, the fires are drawn at once, and it is lowed to cool.-ESAITCHARE.

[4144.]-FIRE CLAY.-Fire clay cannot be made, but got out of the earth the same as coal and other minerals. "Amicus" can buy it. He will find it best to buy his pipes from some dealer in building materials in his own neighbourhood.-ESAITCHARE.

[4202.]-BALANCING LOCOMOTIVES.-By this I suppose "Staem" means putting weights in the wheels to balance the moving parts of the machinery. For that purpose the simplest way for an inside cylinder engine 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, they are so keyed on to the axles as to be in opposition to the inside crank, and, consequently, he weight of the outside rods must be deducted from he weight as found before; and when six wheels are coupled, the outside weight so nearly balances the inside weight that usually no balance weights are required. In the case of outside cylinder engines, the whole of the weight of the piston, rod, cross-head, connecting and coupling rods, and cranks, has to be balanced as far as is 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 glad, as soon as I can find time, to contribute a paper on the subject of balancing moving machinery.-Q. Q. R. [4206.] CHROMATIC

[blocks in formation]

comparatively little.-J. R. D.

[4253.]-TODHUNTER.-I think the meaning of the
quotation is that the symbol, and never another symbol
is used to denote the ratio of the circumference to its
= diameter, or circ.
diameter. Circumference
R = 2 Rx, hence the half of the circumference R
X, and if the radius = 1, the half circumference = ",
but the half circumference = 180 = 2 right angles.
hence we may represent two right angles by, but this
is not invariable, as others represent it by 180° or by H
(hemicycle).-BERNARDIN.

[4262.]-CORNISH ENGINE.-Additional to "F. P."
I send tracing of cataracts of Wicksteed engine at

[blocks in formation]

East London Water Works, Old Ford, which stand on a floor far below the cylinder, one on each side, and are both worked together by the plug-rod, which comes straight down from the beam; the action being as follows: As the plug rod comes down, the chock C catches both cost is too much.-ANON. the cataract lever LL, and turning the wheels W W, which by chain and lever raise the plunger P and the [4226.1-DOUBLE STOCKS.-The reason why double-counterbalance weight T. As soon as the engine begins flowered stocks never produce seed is, because in a real to "go out of doors," the plunger P descends under the good full flower the stamens and pistils are transformed action of the weight T, and this descent is made more into petals; hence it is minus seed-producing organs. or less rapid, as desired, by opening or closing a cock The other In saving single plants for seed, it is a good plan to under the plunger by means of the rod R. thin the blooms, so as to leave (say) half a dozen on each rod S has a loop at the lower end, and when plant, and to give plenty of manure, but guard against the stud V reaches the top of the loop, the rod an excess of moisture to the roots. They should be S rises and opens the valve to which it is appropriated. planted so as to receive all the rays of the sun possible. One of the cataracts opens the equilibrium valve, and If "Saul Rymea" carries out the above, he may get 75 the other opens first the exhaust, and, after a short interval the steam-valve. These are all closed again at the proper times by chocks on the plug rod catching hold of horns on the different valve levers as the engine When the cataracts are placed on comes "indoors." the engine floor they are made ornamental (see fig. 2),

per cent. double flowered.-S. 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 better 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 soon as the piston is allowed to
the valve V closes, and the water escapes by the cock E
descend by the commencement of the "outdoor" stroke
faster or slower, according as the cock is more or less
open, which is regulated by an endless screw (not
shown) working in the 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
But I
Steam Engine," Part I; price 3s. 6d.; Weale.
send him a tracing of half of the beam of the Wicksteed
engine to explain a little of the matter. A C is half the
beam; CD is the main link, 5ft. long; B E another link,
also 5ft. long, to which the air pump-rod is attached at
F. JH is another link for feed-pump, and corresponds
to the link for plug-rod in "F. P.'s" question. Now, the
first rule to remember is that D FHA must all be in a
straight line, or, which is the same thing, CD, BF, 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 AG is a
straight line, and all the links C D, B F, and J H are
kept parallel to each other by the parallel bars DE and
LH, or, if you like it better, E R, therefore D E K will
likewise move vertically. Now, to make F move verti-
cally, you have only to make

GEXEF = BFX BA.
Now, in this case A B = 8" 5 = 1011"
B C = 6" 11 = 83,

and C D 5ft. = 60in. Now, by rule of three, as

[graphic]

AC: CD::AB:BF

184 60 101: 83,

and F E is 60 -38 27in. So, to find G E, which
33 × 101
=124in. for the
we have
27

BFX BA

EF

GE=

length of C E the radius rod. Another way to get
the same result without calculating B F first is to say
10112
A Bla
or GE=
= 124in., as before. The
83
BC
radius rod in the drawing from which I take the trac-
ing is 129in. or 5in. too much, which accounts for
what I think I remember used to occur at the
end of the indoor stroke of that engine viz.,
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 find 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 Piston
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 "Exercises in Mechanics," or Newth's "Mechanics" for information similar to that required to solve his question.

Leth height of water = 18ft.
b = breadth of gate

c = centre of gravity

then area of gate = 18 x 11ft.
and pressure

= 11ft.

18

=

= 9ft.

2

= 18 x 11 x 9 x 62.5 = 111,8751b. 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 11ft. area and 9ft. high-18 x 11 x 9 = 1,782 cubic feet. The weight of a cubic foot of pure water is 1,000oz. avoirdupois; so that 178,200oz. or 4 tons 19cwt. 1qr. 21lb. 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 the 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 are the best for most ordinary purposes.-A. J. JARMAN.

[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 Strasbourg, 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° B., c, by their specific gravity. By the first process, the oil being heated in a porcelain capsule over a spirit lamp, the peculiar volatile odour of fish, linseed, or other oils may be detected, especially if compared in the same 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 a glass rod, two different reactions are observed-viz., drop of sulphuric acid is brought in contact with it by 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 Olive oil-first, pale whole becomes almost brown. yellow passing into greenish-yellow; second, yellow, Linseed oil-first, dark reddishmore or less gray. brown, afterwards brownish-black; second, brown-black. Whale oil-first, red, passing to violet; second, brownishred, passing to violet. Sesamum oil-first, red. Poppy oil-first, yellow, or greenish-yellow; second, yellow on white or grey ground, &c., &c. An unadulterated oil of the same kind should always be examined with the suspected one. The characteristic reactions vary also somewhat according to the age of the oil. Other particulars, see "Dictionnaire des Altérations and Falsifications," by M. A. Chevallier, Paris, 1870 (op. 417), vol. is

[blocks in formation]

[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 prevents the passage of the gas. If the water level be too low 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 the whole circuit and is just enough to do the work, and also when the battery alone is in cir

cuit; if the latter is more than double the former, he may diminish the porous surface by soaking and drying the 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 endosmose to the utmost, and limit the action of the porous partition to the exact quantity required for the current.-SIGMA.

-IGNORANT IRISHMAN.

[ocr errors]
[ocr errors]

modifying the cause. Either put the aquarium into a
shadier place, or during the 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. The best
vegetation for an aquarium is the green film which
covers the stones or rockwork of either salt or fresh
water aquariumns. After they have been some time in
operation, these can be made to grow freely or other-
wise, by the means indicated above. Pond, river, or
marine plants of the higher order seldom do any good.
Exception must be taken, however, to Valisneria spiralis,
a grass-like plant, which grows freely in a fresh-water
aquarium, is very ornamental, and gives out a good sup-
Phor. Yeh windormition office of these plants to pro-lining-out shafting, say about 50 yards long, and c
duce. Further information if desired.-T. G.

[4380.]-AQUARIUM.-Scrub the sides with a tooth-
brush tied to a stick, and when the scum has settled
put in a bent tube nearly touching the bottom (as a
syphon), suck out the air, and all the impurities will
follow. Also keep up a supply of trumpet snails (Planor-
bis corneus and carinatus), which feed on the confervoid
growths. The fresh-water periwinkle, though orna-
mental, 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
aloides), with starwort floating on the top of the water.-
AMATEUR.

NOTES AND QUERIES.

[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 battery or [4354.]-COPPER MEDAL.-Will any obliging cor magnetic magazine." Has "Beriro" been misled by respondent translate the inscription on this copper the name? Amagneto-electric machine," which is an medal, the head of which is very beautifully engraved, apparatus for obtaining a current by means of perma- and tell me its probable value? Obv. Bust to right nent magnets, is a totally different thing, and depends" CAROLVS XI. D.G., REX. SVECIAE." Under the upon the fact that when a magnet approaches or recedes bust "I.C.H." Rev. In ten lines, “52 F. Nat. 1655, C. from a wire, a momentary current is induced in the wire. 1675. Reoperatis Provinciis Germ. et Danis Extorta Pace Absolvtvm Imperivm in Regui Emolym. Exergvit [4296.]-GALVANIC BATTERY.-J. S.'s" question M. 1697." Size rather larger than a penny.-TATIUS. is inconsistent with electrical laws, and can only be [4355.] ART DEGREES" AND "MATRICULA. answered if further particulars are given as to the con- TION EXAMINATION."-It was with much disappointditions. If there is little external resistance or work to ment that I read J. Harrison's answer (p. 357) to my be done, the proportions of work can be seen at once by query on "A. A. Degrees," as I am eighteen months in the figures given in my papers on each cell, as they were advance of the age he quoted, consequently I cannot obtained by strictly comparable cells. If there is any compete. But if he will be kind enough to give me any considerable external resistance or work a Smee made information as to the necessary requirements for the of plates a yard square, would give less current than a matriculation examination, or how to obtain such, I Grove's liu. square. All depends on the relation shall be extremely obliged to him; and whether there between the electro-motive force and the resistances, is any other degree that can be competed for, without and therefore each case must be considered on its own matriculating; also the age. Or perhaps some other conditions. These points are little understood by gentleman of the noble ENGLISH MECHANIC staff could amateur electricians, many of whom seem to think a give me the required information.-BERIRO. galvanic battery has some magical properties, and therefore I 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 are unequal as to tension. If the two ends of the secondary wire are led to the connections of a delicate galvanometer, and the primary connection with the battery made by hand, at each make the needle will swing to one side, returning to zero, although the contact is sustained; on breaking circuit the needle will swing to the other side and return to zero, and some estimate may be formed from the extent of these swings, but to test the actual quantity some chemical reaction must be effected by nid of a commutator separating the two

currents.-SIGMA.

[4298.]-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. JARMAN.

[4320.)-BREAM FISHING.-If "Pompey" wants to know the best baits for bream, I think I can help him. The tail of a lobworm used with the Nottingham tackle, is capital bait for 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 greaves 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, put the slide in the oven after raking out the fire, and let it remain until the morning, when the hard Balsam can be scraped off, and the slide is ready for the cabinet. If " C. R. H." wishes to mount a cricket whole, he 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 the usual way. Petals of flowers will not require any soaking, and the fresher they are, the better. They are best 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 the same way as balsam, except that no heat is required, and that the cover will want a ring of gold size painted round it, to hold it on. Dry mounting is the easiest of all. Merely place the object on the slide, put the cover on dry, and paint a ring of gold size round it, and the thing is done. I hope

"C. R. H." will have better success next time.-HENRY SUTTON.

[4351.]-CONIC SECTIONS.-See Mr. Proctor's letter. [4380.]-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 the thing complained of. The cure consists in removing or

[4356.]-SOFTENING SKINS.-Can any of your numerous readers inform me how to soften skins that have been cured with alum, arsenic, corrosive sublimate, &c.? I want to make them pliable, so that they can be stitched together, in order to convert them into a hearthrug ?-COUNTRY VET.

[4357.)-COLL.-Can any one inform me how to make a good coil not longer than 1ft. 3in., to give spark in air 1ft. long, and whether I could use the same with a weak cell for small experiments? and how many of the best and what kind of cell it would require, how much wire, size of tinfoil, &c., for the Rhumkorff style, and what would the wire cost ?-A YOUTH.

[4358.]-COPAL VARNISH.-I have about one gallon of good copal varnish. It has been kept in a common can with wood plug for a year, and does not set under 24 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.

out success.
the tank to destroy them? I have tried lime, but with-
engine boiler with water from this tank, I am obliged to
I also find that since I have fed my
clean the boiler every fortnight, instead of every two
months, when fed by the same water from another tank.
Could any of your readers inform me of any substance
which would readily precipitate the muddiness in this
unfit for cask-washing purposes?-COUNTRREWER.
tank without injuring the boiler or rendering the water
[4367.)-RE-ENAMELLING ZING CLOCK DIAL-
How can I re-varnish an old zinc clock dial white
SHEFFIELD FLOOD.
SHAFTING.-Will any
your kind correspondents explain the usual method f
the pedestals for same ?-W. M. M.

[4868.]-LINING-OUT

have been discussing the emigration question kind
[4369.]-EMIGRATION.-Will some of those who
state whether it would be advisable for a watch joble
to emigrate to Australia ?-JOBBER.
height; and standing perpendicularly, what part of
[4370.]-PROBLEM.-Suppose a pole to be 10
pole will have to be cut off for it to touch the endda
base line 80ft. from the bottom of the pole, which is
pendicular to the base ?-SUN BEAM.

[4371.]-CHANGE WHEELS.-Could our friend. k. Slater, or any of our cotton-spinning friends, give a rás to find the change wheels for jack-lifter, cone, and ratchet wheels for roving frames ?-GOOD WORDS.

[4972.)-THE HAUTBOY.-Wanted, a few hints as to how to blow the hautboy, and the kind of reed to selec; and what should be the cost of a good reed.-ANON. [4373.-TO "SIGMA."-Can Sigma" explain the the electroscope that he recommends on p. 273, No. 4 following?-The other day, as I was experimenting with arranged the electroscope so that the pith ball hand Vol. X., I noticed a very curious thing. Having firs thread, and took off the gutta-percha ball on the other nearest to the stem, I hung a pith bull on by a linea end of the wire. I then excited a plate of gutta-percha with a dry silk handkerchief, and applied a proof plane I touched the plane and then withdrew it from the plate and approached it to the other end of the wire, on which the pith ball hung, in fact to the place where the indiarubber ball was; as soon as it came near the ball receded from the stem, and receded as the proof plane approached the wire, until it came near enough to spark. If this is repeated once or twice the ball goes further away than it did the first time, but after that it will go no further. I also noticed that while the ball under the influence of the electricity is 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 of my observations, which I was at a loss to understand, but I have no doubt that you can explain them satisfactorily. Also can you tell me where to get the green carboys in London that I have often seen recommended in these pages for making the cylinder electrical machines, and also the cost of them ?ELECTRON.

[4374.]-PRINTING.-Would some one inform me of a way to transfer ready printed matter to zine plates, so CUTHBERT. to be able to take impressions from them?

[4875.] RED BRONZING.-I should feel obliged if any subscriber would tell me how the red bronzing on chandeliers, gas brackets, &c., is done. I understand the green bronzing and lacquering, but not the redVIRGIL.

[4376.]-COD LIVER OIL.-Can you or any brother reader tell me of a substitute for cod liver oil? I have been frequently advised to take it (being of a weak constitution), but I cannot master it; the sight of it being often too much for me. I would be glad if any ODG could tell me of anything more palatable, and as godA MECHANIC.

[4377.] - TEMPERING BRACE-BITS.-Will any
reader of the ENGLISH MECHANIC inform me how I ca

harden a set of polished brace-bits, mine being all too
soft? They ought to have been good, as they cost £16.

[4360.]-GALVANIZING NAILS, ETC.-Will some
&c., and whether there is not some other and better wayA MECHANIC.
brother reader please tell me how to galvanize nails,
to coat wrought-iron articles with tin, zinc, or copper
without dipping them in molten spelter ?-MARK
STEWART.

[4361.]-METHYLATED SPIRIT.-Will any brother
and why it is not allowed to be used in preparing tinc-
reader inform me what methylated spirit is made from,

tures ?-SHELLAC.

[4378.]-HOW LL.D.'s ARE MADE.-I see you allude in a somewhat satirical way in your last number to "Doctor" Bedford. I don't know whether he is a D.C.L, don gentlemen have recently been putting LL.D. afte LL.D., or M.D., or what besides. I see two La their names, or others bave been doing it for them. I LL.D. Now Mr. or rather Dr. Langley as the Preside allude to J. Baxter Langley, LL.D., and W. C. Eenn of the Sunday League I know, and I have heard of W contrary, these gentlemen may have honorably Bennett, but not as a Doctor. For what I know to @ their degrees. But I should like to know a little 28 the modus operandi. I know a smattering of Latin❤ [4363.]-LIMEWASH ON MASONRY.-Can anyone read French, am pretty well up in mathematies tell me what will remove old limewash from masonry ?graphy, and music; and I should like to be an D. I have a lot to remove, and don't know of any substance Will some one enlighten me as to the how and the exthat will do it. Perhaps you or some of your readers do. pense?-AN AMBITIOUS ONE. -AGENT.

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

[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 some kind brother reader assist ?— S. W.

any en

[4365.]-INDICATOR DIAGRAMS.-Will
gineering reader oblige by giving the best rule for cal-
culating indicator diagrams to find the horse-power of
the steam engine? Also the rule for finding the lap and
lead of the slide-valve to cut the steam off at any part of
the stroke that may be desired? Perhaps T. J. O'Connor
or J. Baskerville can assist me.-A FIREMAN.

tank (open to the air, painted inside), which is supplied
[4366.]-INSECTS IN WATER.-I have a large iron
with water from two sources-rain-water, and water
cooling worts, the pipes being iron (whilst refrigerating,
pumped direct from a well through a refrigerator for
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 a
great number of little insects infest the water, which I
cannot get rid of. Would any of your numerous readers
inform me of any substance which I could throw into

to

[4379.]-BORING CYLINDERS FOR MODEL EXGINES.-Will any kind correspondent tell me how to bore the steam ports and channels in a model engine? I have a solid casting, and, although I can manage to bore the cylinder itself, I want to know how I am to set about making the channels which admit the steam the top and bottom of the piston? I have not any tools, and I know nothing about the work.-SABBAS. name of colza made from? [4380.]-COLZA OIL.-What is the oil known by the in the process?-SABBAS. Is there anything peculiar

[4881.]-COURT PLASTER.-How is this made; and why is it called "court" ?-SABBAS.

our valuable paper inform me what the following coins
[4382.]-COPPER COINS.-Can any brother reader of
are? 1. Obverse: Bust to right, "Diva Faustina." Re-
verse: Female standing beside an altar on a tripod,
Augusta S. C."-2. Obverse: Bust to right; "Imp.
Caes.
an Aug.. ME O XI." Reverse: A
teraple between "S. C.,"
"Aug. below. They are
copper, and very thick, about the size of a penny.
HASTINGS.

.

could spare me a corner in the ENGLISH MECHANIC for [4983.]-THREE COINS.-I should feel obliged if you the three coins enclosed, and perhaps Mr. Henfrey, or

[merged small][ocr errors][merged small][ocr errors][merged small][merged small][merged small][ocr errors][ocr errors][ocr errors]
« ZurückWeiter »