155 mination," as he rather sanguinely an Appendix of very useful Tables, expresses it. To mention one of which show, by inspection, the super-' these, is it likely to obtain, in every ficial content of any board or plank, ' situation where gas-works are esta without having recourse to duodeciblished, a sufficient supply of water, mals, or cross multiplication. Al. of that degree of purity which is ne- together the work leaves little to be cessary for the purpose of filling the desired; and being as cheap as it is baths? Still, however, I thank him complete, ought to be in the hands for the hint, and hope the Mecha- of every cabinet-inaker, chair-maker, nics' Magazine will be the means of japanner, gilder, and lackerer. We informing that important part of the shall quote, as a specimen of the community (the labouring classes) original matter it contains, the folhow they may derive that advantage lowing useful directions to workmen, from tepid bathing at home, and at with respect to the choice and maan expense within their means,which nagement of their tools : has hitherto been enjoyed, at established watering-places, almost ex. “With respect to choosing the tools clusively by the fashionable and used in the trades to which I have alopulent.

luded, the most necessary, and in which I am, Sir,

all may be comprehended, are planes,

saws, and chisels ; and we will consider Your humble servant,

them with respect to the wood they are B

manufactured from, and the steel which Tipton, June 6th, 1825.

form the cutting part of them. And, first, beech is in general, and ought to be always used, for the purpose of the stocks,

handles, &c., as it is of a tough texture, CABINET-MAKER'S GUIDE.

and not liable to split or warp so much

as any other. Now there are two kinds Neu Edition, 95 pp. 16mo. price 1s. 6d. of beech, usually known by the names of

black or red beech, and the white beech; Every Carpenter is acquainted

the former is by far the besć in every rewith a little work under this title,

spect, and may be always known by its which has been published for some

colour and texture, which is darker and years, and held deservedly in consia

more hard in substance; the white is derable estimation. It must be ad- also more apt tu warp, and soon wears mitted, however, that it was open to with use ; it should therefore always be much improvement, particularly in rejected as improper. Again, if you the practical application of the rules examine a piece of beech endways, you and cautions necessary to be observed will perceive the grain run in streaks, by the workman to ensure success which, among workmen, is called the in his operations, and that it left beat of the wood; and in all planes this many subjects connected with the grain or beat, which is the hard fibrous general plan wholly untouched. In particles of the wood, should run in a the present edition these deficiencies direction perpendicular to the face of the have been very ably supplied, by a plane, which in that case appears full of hand evidently well and practically little hard specks; whereas, if the beat acquainted with the art of cabi- runs parallel to the face, it will appear in net-making in all its branches. It not irregular streaks, which situation of the only embodies all that was useful in grain should always be avoided, as the the original Cabinet-Maker's Guide, face will be apt to wear uneven, and and adapts to practice the rules there more subject to warp and twist. Again, contained, but contains a great deal in saw-handles and stocks for bits, the of new matter of the most valuable beat should run in the same direction as description. We would particularly the saw-blade, or in the same direction instance the additions under the head as the stock, when laid on its side. In of Varnishing, French Polishing, moulding - planes it is very frequently Gilding, and Buhl Work; as also the case, that pieces of box are let into


EFFECT OF SCIENTIFIC READING. that part of the face that forms the quirk ness, and that the hairs are sufficiently of the mouldings; but that, when possi- mixed, so that taking hold of one hair, ble, should be avoided, as the texture of it will not pull out or separate from the the two woods are very different, and rest. The larger brushes are usually the different temperature of the atmo- made of bristles, the smaller of camel's sphere will cause a difference in their hair; the former must be firmly tied to contractiou, and consequently the plane the handle, and the string well glued. will be liable to cast. If it is at any time The latter are best put into a tin case, introduced, I would recommend only a and after being used must always be small piece just at the mouth of the cleaned according to the directions given plane, firmly dovetailed in, which will in the course of this work, not be so apt to derange the accuracy of “ By paying proper attention to these the plane.

directions, and a little care, the work* With respect to saws, chisels, and man will be enabled to keep his tools in other edge-tools, their goodness depends order, and to select such as are proper upon the quality of the steel, which for the purpose they are intended.” should be uniform throughout, and it is always better to have thein tempered rather too hard than soft, for use will re- EFFECT OF SCIENTIFIC READING. duce the temperature: or if at any tiine SIR, -Although there is now such it is necessary to perform the operation a general strike for an advance in yourself, the best method I can recom- wages among workmen of almost inend, is to melt a sufficient quantity of every trade, I feel the greatest plealead to immerse the cutting part of the sure and satisfaction in giving you tool. Having previously brightened its the gratifying intelligence, that not surface, plunge it into the melted lead one of my men who is in the habit for a few minutes, till it gets sufficiently of taking your valuable little work, hot to melt a candle, with which rub its is among the disorderly. On the surface, then plunge it in again, and contrary, they endeavour, by what

colour (but be careful not to let it turn prevail upon their fellow-men to reblue); when that is the case, take it out, turn to their duty. I confess, that rub it again with the tallow, and let it at one time I had a strong prejudice cool; if it should be too soft, wipe the against the mechanics attending to grease off, and repeat the process with- such a thing as science; how my out the tallow, and when it is sufficiently views of the case are altered, I need hot, plunge it into cold spring water, or not tell you; I can only say, you may water and vinegar mixed. By a proper now reckon meas one of your greatest attention to these directions, and a little admirers and constant readers. practice, every workman will have it in

From yours, truly, his power to give a proper temper to the

A MASTER. tools he may use. If a saw is too hard, May 31st, 1825. it may be tempered by the same means; but as it would be not only expensive, but, [We are gratified by this testimony in many cases, impossible to do it at to the beneficial effect of our labours, home, a plumber's shop is mostly at but hope it will not hence be inferhand, where you may repeat the process red, that we concur in the opinion when they are melting a pot of lead. But which the words of our Correspondhere observe, that the temper necessary ent seem calculated to convey, that is different to other cutting tools ; you all strikes for advances of wages must wait till the steel just begins to turn are necessarily “ disorderly,and a blue, which is a temper that will give it breach of “duty.We can conmore elasticity, and, at the same time, ceive cases in which workmen have sufficient hardness.

no other means left of obtaining jus“With respect to choosing your brushes tice; but, to be fully justifiable, they for varnishing, it is necessary that they must, of course, be unaccompanied possess elasticity combined with soft- by violence or intimidation. EDIT.]


two figures in the multiplicand, the SIR_The method commonly made product must, of course, consist of use of for measuring a ship's way at sea, or how far she runs in a given

third figure from the right-hand to space of time. is by the loc-line and the left is, in numeration, accounted half-minute glass. It is clear to me,

the place of hundreds ; therefore I that a machine might be constructed ca

tan call the commencement of the leftwith a dial-plate, similar to that of a

hand scale at A 100, and, of course, perambulator, which might be di

the commencement of the right-hand vided agreeably to the rules of navi

one 1000; therefore our figures stand gation. If such a machine has ever thus, 3000+ 600 + 50, nearly. Now, been made use of, any Correspond

as the scale is not long enough to scription of it in the Mechanics'

multiplying the right-hand figure of Magazine.

the multiplicand by the right-hand I am, Sir,

figure of the multiplier (in my mind)

that 48 is the product; hence I know Yours respectfully,

that the last figure of the product MM (of 48 x 76) I am seeking is 8, and,

therefore, instead of 50 I write 48; hence we have 3000+600+ 48=3648,

the answer required. THE USE OF THE SLIDING RULE. Now, with regard to Example the (Continued from page 132.) Second, where the product consists

of five figures, they are thus found : PROBLEM Í.

- I place the l on the line B, as near To multiply numbers together. as I can estimate, at 498, that is, 4 of RULE.

the large divisions on the left-hand Place unity or lon the upper line scale, 9 of the smaller ones, and, as of the slide, marked B, to the mul.

near as I can guess, 8-10ths of a tiplier on the line marked A on the

small division. I then find that, as rule; then against the multiplicand

there are three figures in the multion B is the product, as A.

plicand and two in the multiplier,

there must be at least four figures EXAMPLE 1.

in the product, which is the place of Let it be required to multiply 48 thousands in numeration; I there. by 76.

fore call the beginning of the left, Set 1 on the line B to. 76 on the hand scale 1000, and therefore the line A, then against 48 on the line beginning of the right-hand one B will be the number 3648 on the 10,000. I then look opposite 82 line A, which is the answer required. on the slide B, and I find 4 large

divisions, which is tens of thousands; EXAMPLE II.

therefore we have 40,000, and I find Multiply 498 by 82.

it does not reach quite to one of the Set 1 on the line B to 498 on the

small divisions; therefore the number line A, then against 82 on the line B

stands 40,000, and not quite 1000. stands 40,836, the answer.

But I estimate it, as near as I can, to NOTE.

be about 2-10ths of a small division. It may be here asked, How, in the Hence we have 40,000+800=40,800. First Example, I find the number But, if I wish to be very exact, I find, 3648 opposite to 48 on the line B, by multiplying the two last figures which appears, by the inspection of of the multiplicand by the last figure the rule, to be at 3 of the large divi- of the multiplier, the two rightsion of the right-hand scale of num- hand figures will be 96; hence I am bers marked at A, 6 of the small certain that the last figure of the division, and about half another ? product will be 6 for the unit's place. This I will endeavour to explain as I then again multiply the last figure follows:--We know that, as we have of the multiplicand by the first figure two figures in the multiplier and of the multiplier, which gives me a


INQUIRIES ANSWERS TO INQUIRIES, 4 in the unit's place (viz. 64); I then Sir,-Your inserting the followadd the 4 to the 9, which is 13; I ing inquiries in your very useful know, therefore, that 3 is the figure iniscellany, will oblige for the tens place : our operation

Your obedient servant, will then stand thus, 40,000 + 800 +

N. E. 30+6=40,836, the answer.

Cork, April 9th, 1825, : And here it inay be observed, that though I have shown how the operation may be performed to the extent of five figures, it is, in actual practice,

No. 129.-TEST OF BAY SALT. of little consequence to the mea. The test for ascertaining the qua. surer who is in the habit of using lity of St. Ubes, commonly called the rule, being chietly confined to Bay Salt, and the reason why some the journeyman carpenter, sawyer, samples dissolve sooner than others ? &c.; and the dimensions they have to A house in this city, very extensively take scarcely ever exceed two figures engaged in the manufacture of profor the multiplier and two for the visions, purchased a cargo of very multiplicand, for in that case other fine-looking salt two years since, but methods are found preferable. complaints" were received from all

These observations will apply to quarters of there not being salt any of the followiny Problems; I enough, though the usual quantity shall therefore only give them as was put into the cask. The salt was regards the method of using the rule of a fine white colour and large grain. for their solution. -

G. A. S.

No. 130. HOW TO CLEAN MOULDY (To be continued in our next.)

The manner of cleaning mould,

&c. from Russia and other leather ? INQUIRIES

NO. 131.-CAUSE OF SALT BERP No. 127.

SPOILING. ELLIPTOGARAPHIC INSTRUMENT. Some beef, in tierces, has been · Sie-A description is desired of returned from England, unsaleable, the best elliptograph for drawing having become black. The cause is ellipses of the smallest size, with required. Does it arise from the salt their diameters in any given propor- or saltpetre ? and how could it be

tion, without having to shift the in remedied ? · strument before completing them ?

I am, Sir,
Your obedient servant, ANSWERS TO INQUIRIES.
C- MI .


MACHINE. No. 128.-FELT SHOES AND GLOVES. SIR,- I think your Correspondent • Sir,-We remember seeing, some

F. S. M., vol. 11., p. 415, will find years ago, a pair of Felt Shoes, and,

that the weight of the line itself (if the other day, a pair of Felt Gloves.

suspended during the experiment, as

I apprehend it must have been), beIf any of your Correspondents could inforin us where or by whom they

tween the spring machines and the are manufactured, they would very

carriage, will be nearly equal to the

difference in the scale of weights greatly oblige,..

drawn forth. It is well known to

seamen, that a long cable materially Your obedient servants,

assists itself by its own weight, and IlayDS AND FEET. that less strain is brought upon the



169 anchor by a long cable than a short no. 100.--CUTTING AND POLISHING one, the strain on both being less CALCAREOUS STONES, ETC. ened by the weight hetween the

Sir,-A Correspondent who signs ship and the anchor. This is parti

himself “ Lapis," in p. 352, Numcularly exemplified in the use of

ber 78, is desirous of information chain as cable, the difference in

respecting the best method of Cutweight compensating for the differ

ting and Polishing Calcareous and ence in length in the proportion of

Siliceous Stones; if you think the two to one. Thus, with a chain

following description of a Mill is cable of 100 fathoms, a vessel is sup

worthy of insertion in your Magaposed to ride as safely as with a rope

zinc, it is very much at your service. cable of 200 fathoms.

The apparatus is extremely simple Should my attempt at elucidation

and convenient, and may be made by afford F. S. M. any part of the in

any one poseessing a lathe. It is not formation he requires, it will give

new, but has been sold for some me much pleasure.

years by Mr. Mawe, in the Strand, I am, Sir,

at from six to eight guineas. The Your obedient servant, accompanying drawing represents a

R- , M . section of the apparatus.

[ocr errors]

AB is an oblong wooden box, in

No. 116. which the axles, CD, FG, revolve, and which serves also for a case.

CONSTRUCTION OF CHIMNEYS. E represents a wheel with a grooved Sir,- The best form or construcedge, and at H is a series of smaller tion of chimneys I know of, for conwheels, likewise grooved, by means veying the smoke, is that of the of which the velocity of the mills circle, which should not be less than may be regulated at pleasure, and the one foot in diameter for a commonstring which connects them may be sized apartinent. I am aware, howmade more or less tight. At the end, ever, that this forın is objected to F, of the axle, FG, which projects by architects, as it requires one-third through the top of the box, is a of brick extra in thickness for the screw, on which the different mills chimney shaft. As to the cause why for grinding and polishing are to be so many smoke the wrong way, I fastened, and by turning the handle, think it is owing more frequently to C, it is at once obvious that they the carelessness of the bricklayer in will revolve with great velocity. The building than to any thing else. In string may be of catgut, or any thing fact, neither the architect nor the else more convenient.

clerk of the works ever pays much In this manner hard siliceous stones attention to them. Sometimes they may be ground down on the lead are too suddenly contracted at the milí, with emery, in a few minutes, throat of the flue (a little above the and afterwards polished on different arch of the fireplace); and in other mills, using flour of emnery and putty cases, when the flues run crooked, When slitting is required, then the the bricklayers contract them to not slitting-mill, consisting of a thin more than nine inches by ten inches, . plate of iron, is to be screwed on, nay, I have seen them less than that.. and the stone to be cut applied to The waste lime from the trowel, too, its edge.

J. M. N. usuallyfinds its way down these flues,

« ForrigeFortsett »