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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-
A lesson of hu-
versally diffused throughout creation.
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

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

FISHING RODS AND TACKLE.

[150] SIR,-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,

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 e
plain. Now, armed with the above necessaries
fly-book, a pair of scissors, a baiting needle
gorger, some spare gimp and gut traces, and an e
ment of Limerick hooks, a live-bait kettle, a larg
worms, some split swan drops, and one or two estos
floats, the angler may go to any river or lake u
world and get good sport. He may entice the w
trout, the beautiful char, the elegant grayling, the
pike, the monstrous salmon, the slippery eel, the
white trout, the timid chub, the lazy bream, the gat

lives these incessant changes are never for a single 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 wi without a certain portion of our substance being sacri- any of them to get good sport wherever fish are to be flavoured tench; with the carp, the barbel, and to ficed. In fact, so rapid is the wear and tear, that physiologists calculate that a quantity of material equal to general rod-no doubt it saves trouble in carrying- fishing this year has been particularly good everywher 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

one.

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
becomes attacked, and delirium and death complete
It is by the agency of our daily
the series of events.
food that these losses are repaired. Now it has been
found that the "principles" contained in the human
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 con-
BETA.
ducive to our health and happiness.

gudgeon, nay, even the tiny stickleback itself. In and there is no sport so enjoyable as a day's good id ing-wandering along the mossy banks, inhaling clear balmy air-far from smoke and dust and cae ! for sea fishing.

VIVIS SPERANER

PRESERVING FRUIT, ETC.

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 emergenThis constant waste, resulting from the various cies occur so often as in angling. Therefore, I would may shortly, with your leave, give a list of ace always recommend anyone wishing to become an angler to have a rod that suits the 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 be using. I have known a first rate fly-fisher, when whipping for small trout with a single-handed light fly rod and n fine 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 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.

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:

Yard.

Hour. Seconds. Mile. 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 T. S. USBORNE. complicated.

IRON IN BATTERIES.

[149] SIR,-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 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.

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. 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
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.
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 be
lapped to prevent the joints separating when the rod is
in use.

Raw

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 quesuon 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 The flies next demand our attention, and here let me point acting perfectly. Now, turning to the calculation these, as after using flies once or twice they lose all cell, but, of course, it gives a lower current; in every other say, that it is quite a mistake to have a large stock of (p. 387), it will be seen that the cost of the zine is only their pristine vigour; and if they lie by for a season about one-fourth the total, reckoning it at 7d. per are apt to suffer damage from the moths. Therefore, pound, double what it may readily be got for, as I buy it is preferable to buy a few of the sorts wanted before it at 34d. If we reckon the iron at 1d. only, the dif- going on any fishing excursion. Most rivers have ference of cost will not be a very large proportion of favourite flies, which may be the means of filling a the whole, while the current would be considerably re- basket sooner, but in the hands of an expert angler the duced in force, and thus it becomes very doubtful 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 tront flies are about half the size of a salmon fly generally, with crimson or purple body, and green or yellow wings.

economy.

fetid unwholesome gas given off, owing to the carbon In simple acid cells a very serions 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.

The baits for trolling are very numerous-both live and artificial. I could not enter upon the manner of hookminnows do very well, especially for the Salmo ferox. ing live or dead bait in the limits of this letter. Artificial 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

[151] SIR,-Would any one of our many readers who know how, or has himself preserved fruit, kindly mak known through our journal the modus operandi' T. particular point on which I wish for information is b the tin cases which generally come from America, ectaining peaches, are hermetically sealed. I wished preserve strawberries in this way, and so I filled a tin with them, putting in a little sugar and two or three spoonfuls of water. I then soldered on the top, leavi of course, a small hole. I put the case then on a fire, in order to get the case filled with steam, whi 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 oper them that all were spoiled would be rather disa 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.

WINDMILLS.

Rustic from Berk

[152] SIR,-I have been making experiments on the horizontal windmill. I have made models of those described by Mr. Vallance and by shire Downs," and, as far as my experiments have gone, I think, for practical purposes, Mr. Vallance's is much Its motion is very smooth, and not likely to cause the same amount of wear and tear as the "Rustic's." In the latter the shock to the arms on the

the best.

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change of the sails from the horizontal to the vertical
position very severe unless he can break its force by
interposition of a spring. I mean to compare them
as to the amount of power given off for the same
surface of sail. At present, I think the "Rustie
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 ja
the opposite sails passes, and by the severity of e
strain which the arms are required to bear.

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

Has H. W. Reveley ever seen a horizontal műb the one he describes on page 40 in actual work. proportions he gives seem very large for so little p He seems to be mistaken about the open kor sails, as he says "the wind only catches one sal difficulty of getting the sail frames back aga edge to the wind. There is no such great d wind." What does he mean? there is no ins difficulty. In all forms the sails come back t the air, and that is all that the edge of from wo the vertical, for then, too, the edge has to do in the horizontal, and a little consideration Reveley's part would have shown him that this for though he may say one sail has to come up with edge against the wind, and so cause more resistance that 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 that 2 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 disenssio Vallance, no one who has written has stated that P the horizontal windmill. With the exception of mill did any real practical work. "Rustic from tieshire" has not fulfilled his promise to send drawing his more powerful mill, which he speaks of in his le therefore, any further information as to practiod wers on page 18 of this volume. I mean to make a mill, ark already given me much help, and I think the subje ing would be most acceptable. Mr. Vallance be of a cheap motive power is well worthy of a place DERF ERRAC.

time, and that only for an instant, besides the in

our MECHANIC.

OUR ASTRONOMICAL NOTES. cism on "Astronomical Notes for July." [153] SIR,-I beg to lay before your readers my crit We find the moon comes to the conjunction of Jupiter at 4h. 5

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And not at 3h. 52m. in the afternoon of the 24th. Mercury snot in superior conjunction with the sun on the 28th, he is in conjunction with that luminary on the 27th at 5b. 20m. a.m.

Why has "F.R.A.S." discontinued to give us the time of rising or setting of some of the planets ?

It must be acknowledged by all, that it is far more consonant with reason to give us the right ascension and declination of the sun, or the longitude in the ecliptic, than to state that his right ascension is (on the 1st July, 1870) 6h. 40m. 50-48s., and his declination 23 722-7 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 than the outlines of a fabulous animal. In short, we prefer to say that the sun is in (the sign), and not in (the constellation) II.

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G. FIRTH.

use.

I have some

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. -WALTER J. NICHOLLS.

the weight of air at 14oz. for each cubic foot, it would [2677.]-HYDROGEN GAS FOR BALLOON.-Taking require about 1,970 cubic feet to be displaced to raise 11 stone weight (i.e., 154lb.). Pure hydrogen gas is 144 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.

Univ." t. i. p. 194, says, speaking of Egypt," the dogmas
[2694.]-GREATER PTHAH. César Cantu "Hist.
particular to the priests acknowledge
Supreme Being, who could not be represented by
a unique
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-
tine, under that of Cnef, the symbol of which was a
serpent rolled upon itself."-BERNARDIN.

suggestions for models of harmoniums. 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 one 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 GEOMETRICAL APPROXIMATIONS. 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 cal approximations inserted in the Philosophical Maga- resembling reeds. I cannot understand it, but I am zine, 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 fifth of √2 0 B or O G, producing 3141421.* The there is a very pretty beat in the note, quite a pulse, late Mr. Willich gave, in his Popular Tables," a nearer making a wave of sound dreamy and delicious in its approach, and were my numerical triangulet convertebb and flow. I cannot take the bass part for reeds; it ible to a geometrical appendage it would be very close. is deceptive enough to pass for wood pipes, though in You perceive I found, from considering 3150000 the bottom row of keys there is something quite different, and more like an harmonium. I should be glad 21 84000 = 735 that (3000000-8007 A) gives 314159215 to describe to your readers its effects. I have nearly 20 got what I desired as to loudness and boldness. My old and affixing (1200 2) 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 as a chord, and reducing the an harmonium, but I am informed I cannot get it. supplementary chord in the ratio of the ordinates to Next best to it, I find in the lower row of keys stops of great brilliancy and power. the alscisse of These taken in comof the diameter, producing a parison with those at the top show a great contrast. I find a beauty there. They are not wrongly labelled. I chord exactly equal to 314159265. do not know the Cor Anglais, but the violincello is perPage 374.-Although as an old Fellow of the Royal fect. Also the flute and clarionette. The contra bassa is Astronomical Society, I rejoice at the further extension of the "family likeness" between the constituents of cribed by Dr. Leslie, whose words give a good guide to a power by itself unique. They are not unaptly desother planets with our own, yet is it not premature to what you actually find in the instrument. A little suppose their chemical elements are exactly alike, and pressure by the knee keeps the full power on; it is so as to produce the same sorts of plants and sentient magnificent. Press the other knee swell, and it probeings, knowing as we do the immense terrestrial vaduces an effect of piano, either on one stop or on full riety God has formed out of the few chemical elements, power. I may say I have found in reality twenty-seven oxygen, hydrogen, azote, and carbon? Page 350.-Metrical Act: Referring to the "Com-stops and nine sets of reeds, whilst your correspondent panion of the Almanac " for 1827, page 100, I lately de- harmonium of the future. Thanks, however, to him has been playfully poking his fun at me respecting his duced that (883 000536) pendulum lengths 960 yards per Act of 1824. 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. 3, 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 37289 moon and his limit, give from the secondaries' period the rotation times of the orbs Virg. 603 : 289 :: (27

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[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, unable to do so. and having had to leave home for a time, I have been querist omits to state what stage of the disease he As regards the above disease, the 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 juguing 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 heavy shoe, invented especially for laminitis, or fever in of no better treatment than the adoption of Mr. Broad's the feet (of which I forward a sketch), which has lately

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to Jupiter's EXTRACTS FROM CORRESPONDENCE. of others, I have come to the conclusion that it is the best

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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

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TRACTION.-"J. B." says:-"In reply to Mr. Thomas, page 394, the action of a tramway in reducing the with the obstruction caused on all ordinary roads by draught is, that the equality of its surface does away 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 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 stances; only if the gradient be steep and the load heavy a load on a tramway than on a road under all circumthe 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 20%.; 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-dissolved. Now add the cyanide of potassium until all at the bottom of the vessel, from which the clear solution the blue colour disappears. A precipitate will be found may be decanted. Two cells of a battery will be neceswhich are to receive this deposit should be previously sary to deposit from this solution. Articles of iron 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

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

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

[3716.]-RELACQUERING

BRASS WORK.-" Pro

Bono" should scour his old brass with very fine pumice, thoroughly rinse and polish. The acid will no a quired.-WALTER J. NICHOLLS.

be re

[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 take them up and hang them up to cool, throw away the them well for half an hour in clean water and argol, 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 them up, cool, rinse, dry, and they are done. He says well for an hour, handling well all the time; then take 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 T. K. things by his direction and have found them first-rate.

[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 solumust be stirred continually, and especially at that part tion, and by the heat. To prevent it getting into cakes it 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.

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.

all. The pure article is the carbonate of the metal, and
its commercial value in the dry state averages from 30-
to 36s. per cwt. The adulteration of white lead, or
account of its high specific gravity, would have bee
rather difficult were it not for the existence of a cert
mineral nearly corresponding with it in this res
and of very little use in the arts otherwise. This t
sulphate of barytes, a ponderous, massive,
mineral, occurring in extensive veins, permeating.
volcanic rocks. Two important veins of this des
tion occur in Scotland-one in the island of Arran, f
of Clyde, the other at Muirshields, in Ayrshire-b
which are worked mainly for the purpose of adul
ing white lead. A few years ago, I carefully examini
the workings of the vein, and also the process of m
facture of the adulterant at Muirshields, which have be
in progress for many years. The vein is almost re
upper edge cropping out on the surface in a perfect
moorland and mossy district. The gradual progressi
the removal of the barytes has left a considerable
behind the actual operations, from which I ascertain
as nearly as I can recollect, that the vein var
thickness from 1ft. to 5ft. The direction of the
dyke, as it may be called, extends nearly east an
crossing the Frith in the direction of Arran; and
can scarcely be a doubt that in the dim vistas e
past, long ere Time's erosive tooth had gnawed on
deep and tortuous channels, the far-reaching rock
craggy, savage glens, the endless succession of heather
clad mountains, and the lovely isles which s
up the matchless scenery of our lovely Clyde, th
barytic rock formed
fragmentary seams of

[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 ing about 400 apertures per square inch. The next step cal, having an inclination of probably 5 or 7. 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.

see the grease begin to show a blue flame roll them in clear fire, and rub them over with grease, and when you water, and your springs are tempered.-DEESIDE.

[3875.]-BLEACHING POWDER.-In reply to " Gratus the following is the method of manufacturing bleaching powder:-The lime used for the preparation of this article must be of the first quality, for unless this is attended to the salt prepared from it will be very interior in colour. To prepare the lime for the absorption of the chlorine gas it is brought to the screening department and slaked with just sufficient water as will cause the lime to crumble into a very fine powder; some care must be taken that not too much water is used, or it will be difficult to screen it. The powdered lime is then screened or sifted through fine wire gauze sieves, havto be considered is the preparation of the chlorine gas. This is obtained by acting upon peroxide of manganese with hydrochloric or muriatic acid. The stills used for generating this gas are formed of large stone slabs, grooved and well cemented together, and in the form of a cistern; this is again surrounded by a casing of firebricks, iron, or stone slabs similar to the others. A cavity 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 4t. 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 [3787.]-TEMPERING BUFFER SPRINGS. The lead, supported by a framework of wood, similar to a vitriol chamber. The chamber has two doors, which way I generally temper them is to heat them in a slow are luted close during the time the charge is in. The fire with wood chips, little more than blood red, then bottom of the chambers are formed of fire-bricks. The plnnge them in water; then take and heat them over a size of the chamber and number of stills must be accord the height of the chamber must be about Gft. Having ing to the quantity of bleaching powder to be made; 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 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 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, be cause 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. teur Horologist" will pay a visit to any country clock [3888.]-ALARUM FOR DUTCH CLOCK.-If "Amamaker, and examine a Dutch alarum clock, he will learn more in ten minutes than he would from any description, which would be practically useless without figures.

[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 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.

[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.

-R. T.

[3893.]-PRECIPITATING GOLD.-Chloride of tin will precipitate the 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 band 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.

[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.

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

[3934.]-ORGAN ACCORDION STAND.-If "Sigmatau" will look in No. 153, 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 a regular paint mill, or by hand between two flat stones, the under one large. To apply an alkali, in order to dissolve 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 any white lead at

grand dyke, on the extent of which it would be a
less to speculate. Barytes thus found is generally ké
or more discoloured by streaks or blotches, owe
mainly to the presence of oxide of iron. The mineral
after being deposited at the works, is crushed to a for
powder by means of ponderous iron rollers, revolver
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,
rather in water strongly acidulated by that acid in ta
or vats, which should be lined with sheet lead. T
digestion can be repeated with frequent stirrings art
after settlement. The pure barytes thus obtained a
the bleaching is completed, and all trace of the act
can be removed by repeated washings and decantatia
in this condition is ready for market.
now thoroughly dried in any convenient manner, and
It now only
remains to be told that the manufacturers' white lead
in very various proportions to suit the pocket of the
of commerce is made up by mixing the two ingredients
buyer, or the conscience of the dealer, those proportions
varying from probably 75 per cent. to almost zero of the
genuine article to the corresponding complement of the
the ordinary paint mill with a sufficient admixture of
other. I need not explain that all this is performed in
oil. Taking the value of pure white lead at 35s. 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,
cover so well, nor yet does it mix or combine in so
kindly a manuer with the oil as the more flocculent lead
split partnership with the oil and become a solid
So that "H." should not be surprised if his lead bas

mass.

I have already said that this barytes bas specific gravity alone being often taken advantage of few applications except as an adulterant; its high under circumstances which would scarcely be anticipated. I will just refer to one instance for the benefit of our "Harmonious Cotton Spinner" (I think we have one) and his congeners. The little paper tubes used for placing on the spindles of spinning mules, and which receive the first windings of the yarn, forming in fot the bottom of the cop, are made by rolling upon a sheets of paper pasted on one side, drawn off the win, dried and cut into suitable lengths. Now the pa spinner, although in the first instance defrauded i in this little process is amply charged with barytes De tube maker, has good reason to wink at the dee as he, in turn, disposing of the tubes along with th the extent of the difference. yarns, at maybe some shillings per pound, benefits! The mineral barytes compound of the metal barium, oxygen, and sulp acid. By mixing it in powder with charcoal, and e nace, it becomes reduced to the sulphuret of bas jecting it for a time (in a crucible) to the heat of having lost its oxygen. In this condition it is st acted on by nitric acid, for the formation of nitr barytes, a salt used by the pyrotechnist in the pr tion of green fires. This fact will point out to H he possesses one, a ready means of testing the presc of barytes in his white lead by means of the p as a small piece exposed to the flame would give the or still nearer to that of iron, characteristic green flame similar to that oppet but not pALEXANDRA.

[3990.]-YELLOW DYE.-"A Countryman" lamine yellow, to be obtained of most chemists and try Manchester yellow, otherwise known as Nany

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 Failing to obtain this he must add bismuth to ordinary type-metal, till he gets the cast as hard a 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 re be poured in. It consists of an iron tray made wit closely-fitting lid kept in position by a screw, and hat the corners cut off to act as inlet holes. Into this in the design should be placed "face" downwards; lid screwed down so as to leave the required space thickness of casting; and the casting-box in serted i the molten metal, which should be done in a diago direction to allow the air to escape at the upper corn. The other method consists in having a thick iron b with one end open, made to unclose longitudinally, a leaving space according to the thickness of the cast which it is designed. The mould is then fastened on side of this, the box firmly closed, and placed b

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

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[4218.]-TUBE IN SPIRIT LEVEL.-Take off the brass plate; clear out the recess in the wood; see your tube fits in very easy. Take a little white lead or putty, place it on the bottom of the recess; 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 have 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. East London Water Works, Old Ford, which stand on a (4225.)-ICE. Has a "Warm Countryman," or any floor far below the cylinder, one on each side, and are one else tried Toselli's ice machine-a very simple way both worked together by the plug-rod, which comes of making ice, ice creams, &c. If so, perhaps he straight down from the beam; the action being as follows: As the plug rod comes down, the chock C catches both will let your readers know the results, and whether the 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 under the plunger by means of the rod R. end, and when rod S has a loop at the lower the stud V reaches the top of the loop, the rod S rises and opens the valve to which it is appropriated. One of the cataracts opens the equilibrium valve, and the other opens first the exhaust, and, after a short in terval the steam-valve. These are all closed ag tin 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),

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 planted so as to receive all the rays of the sun possible. If "Saul Rymea" carries out the above, he may get 75 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 RR 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
As soon as the piston is allowed to
above the piston escapes downwards through the side
passages shown.
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 A G is a
straight line, and all the links C D, B F, and JH 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"
BC 6" 11 = 83,

and C D 5ft. = 60in. Now, by rule of three, as
AC: CD::AB: BF

184 60 101: 33,

and F E is 60 -88 27in. So, to find G E, which
BFX BA
33 X 101
= 124in. for the
27

EF

we have

length of C E the radius rod. Another way to get
the same result without calculating B F first is to say
A Bla
101/2
GE=
or GE=
=124in., as before. The
83
B C
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
- viz.,
end of the indoor stroke of that engine
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

b

=

18ft. breadth of gate = 11ft.

18

=

9ft.

2

c = centre of gravity

=

then area of gate 18 x 11ft.
and pressure = 18 x 11 x 9 x 62.5

[blocks in formation]

[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, 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. 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. i

p. 343.

"Die Verfälschung der Nahrungsmittel" &c. Von H. Klenche. Leipzig, 1858, p. 381. Characteristic reactions of some Indian oils, see "Technologist," t. iii., I think particulars are also to be found in the works of Dr. A. Hill Hassall.-BERNARDIN. [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 circuit; 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 zine plate. The point to be aimed at is to reduce endosmose to the ntinost, and limit the action of the 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 battery" or magnetic magazine." Has "Beriro" been misled by the name? A magneto-electric machine," which is an apparatus for obtaining a current by means of permanent magnets, is a totally different thing, and depends upon the fact that when a magnet approaches or recedes from a wire, a momentary current is induced in the wire. -IGNORANT IRISHMAN.

[4296.)-GALVANIC BATTERY.-J. S.'s" 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 resistance 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 comparable cells. If there is any considerable external resistance or work a Smee made of plates a yard square, would give less current than a Grove's liu. square. All depends on the relation between the electro-motive force and the resistances, and therefore 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 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 breaking 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 aid 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.

14320.J-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

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 aquariums. 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-
Plyof oxygen, which it is the office of these plants to pro-lining-out shafting, say about 30 yards long, and seti
duce. Further information if desired.-T. G.

the tank to destroy them? I have tried lime, but
out success. I also find that since I have fec
engine boiler with water from this tank, I am oblig-
clean the boiler every fortnight, instead of every
months, when fed by the same water from anothert.
Could any of your readers inform me of any substa
which would readily precipitate the muddiness in
tank without injuring the boiler or rendering the wa
unfit for cask-washing purposes?-COUNTHEWEE
[4367.)-RE-ENAMELLING ZING CLOCK DIAL-
How can I re-varnish an old zinc clock dial white
SHEFFIELD FLOOD.

[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 syphon), suck out the air, and all the impurities will follow. Also keep up a supply of trumpet snails (Planorbis corneus and carinatus), 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 aloides), with starwort floating on the top of the water.AMATEUR.

NOTES AND QUERIES.

[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 Provinciis Germ. et Danis Extorta Pace Absolvtvm Imperivm in Regui Emolym. Exergvit Size rather larger than a penny.-TATIUS. M. 1697." [4355.]--" ART DEGREES” AND "MATRICULA TION 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 informati. 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 soine other gentleman of the noble ENGLISH MECHANIC staff could give me the required information.-BERIRO.

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

[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 real amber from imitation ?-L.

repolished, and what means are there to distinguish

J

[4868.]-LINING-OUT SHAFTING.-Will any your kind correspondents explain the usual method d the pedestals for same ?-W. M. M.

[4369.]-EMIGRATION.-Will some of these who have been discussing the emigration question kind state whether it would be advisable for a watch-juble 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 endea base line 30ft. from the bottom of the pole, which re pendicular to the base ?-SUN BEAM.

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

[4872.)-THE HAUTBOY.-Wanted, a few hints as to how to blow the hautboy, and the kind of reed to select; and what should be the cost of a good reed.-ANON.

[4373.]—TO "SIGMA."-Can "Sigma" explain the following?-The other day, as I was experimenting with the electroscope that he recommends on p. 273, No. 25, Vol. X., I noticed a very curious thing. Having firs arranged the electroscope so that the pith ball han: nearest to the stem, I hung a pith bull on by a line thread, and took off the gutta-percha ball on the other 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 page 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 zinc plates, so to be able to take impressions from them?CUTHBERT.

AS

[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 good— A MECHANIC. [4377.] TEMPERING y reader of the ENGLISH MECHANIC inform me how I ca soft? They ought to have been good, as they cost £16. harden a set of polished brace-bits, mine being all too

[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.

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

tures ?-SHELLAC.

BRACE-BITS.-Will

[4878.)-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. after LL.D., or M.D., or what besides. I see two Lan their names, or others bave been doing it for them I allude to J. Baxter Langley, LL.D., and W. C. Eennes LL.D. Now Mr. or rather Dr. Langley as the Preside of the Sunday League I know, and I have heard of W Bennett, but not as a Doctor. For what I know to contrary, these gentlemen may have honorably their degrees. But I should like to know a little s the modus operandi. I know a smattering of Latin read French, am pretty well up in mathematies * ?graphy, and music; and I should like to be an LD. Will some one enlighten me as to the how and th expense?-AN AMBITIOUS ONE.

[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.

[4363.]-LIMEWASH 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. -AGENT.

[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 calculating 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. [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 pumped 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 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

[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 to the top and bottom of the piston? I have not any tools, and I know nothing about the work.-SABBAS.

[4380.]-COLZA OIL.-What is the oil known by the name of colza made from? Is there anything peculiar in the process ?-SABBAS.

[4381.]-COURT PLASTER.-How is this made; and court" 2-SABBAS. why is it called " [4382.]-COPPER COINS.-Can any brother reader of our valuable paper inform me what the following coins are? 1. Obverse: Bust to right, "Diva Faustina." Reverse: 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.

[4383.]-THREE COINS.-I should feel obliged if you could spare me a corner in the ENGLISH MECHANIC for the three coins enclosed, and perhaps Mr. Henfrey, or

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