Графични страници
PDF файл
ePub

judgment, and the fact that their engines earn more per eosine per annum than any of the other trunk Is (watle the repairs are not greater) is, to my thinking, conclusive that their practice must be anything but wrong, apart from the fact that their expresses are as heavy as, and the speeds greater tan, any others. The figures for 1875 are:G.N. Mid. G.W. L.&N.W | Earnings per engine £2,841 £2,574 £2,386 £2,360 Receipts per train s. d. 8. d. s. d. s. d. mile ... 52:43 5 3:02 5 5.89 5 10:02

[ocr errors]

Or, with the smallest receipts per mile run, the G.N. ezgines earned the most money. Nor can it be said hat the G.N. road is an easy one compared with he Midland from Leicester to Leeds, or the L. and N.W. from London to Birmingham, for instance. I do not think "C. E. S." (letter Sept. 20) makes a fair comparison between the two N.B.R. engines. There is reason in all things. No loco. superintendent would design a single engine to take heavy express passenger trains over roads where there are gradients of about 1 in 70 for miles, and it is quite possible that the special new engines designed for this heavy traffic, when tried on an easy line against a single engine with about 25 per cent. less tractive power would burn less fuel, as the steam could be used more expansively. There is such a difference between the two engines, that they are scarcely comparable; and if they were, the results of months', instead of days', working would be required to prove that coupled engines for fast traffic on average roads are more economical than single engines. I cannot do more than quote Mr. P. Stirling's remarks recorded in the "Trans. Inst C.E.," Vol. XXXVII., which, to my mind, are as sound now as they were then, and have never been disproved. Speaking of the 8ft. wheel bogie engines, he says, p 31:-"With regard to the power of the engine, it had taken a train of 33 carriages full of passengers from Doncaster to Scarboro' and back, at a speed of about 45 miles an hour." And, p. 57," that he had constructed two classes of engines for passenger trains, one class with four wheels 6ft. Gin. dia. coupled; the other with a pair of 7ft. driving-wheels. Both engines had similar boilers and cylinders 17in. dia., with a length of stroke of 24in.; the pressure of steam in the boilers was 140.b. On his frequent journeys to London he had been in the habit of noting the size of the trains, and the class of engine used. He found that with a similar train in both cases the single engine had fully the best of it-in fact, generally beat the coupled engine in time to Potter's Bar, a distance of nearly 13 miles, and nearly all up bill, the gradients varying from 1 in 105 to 1 in 200. This Jed him to think that sufficient adhesion could be got with a single pair of driving wheels, and he believed no one would doubt the superior freedom and economy of a single engine over a coupled one. He considered the usual cylinder power was quite nadequate to the required adhesion in nearly all

engines.

"In designing the (8ft. wheel) engine under consideration be determined to have a large wheel, being satisfied that the larger the wheel the better the adhesion to the rail; and as inside cylinders could not be used, in consequence of the height of the cranks he put them outside, where he could get them between the wheels of the bogie, and in a horizontal line with the centre of the driving wheel. The tractive power of this engine, by calculation, was 15 per cent. more than that of the coupled one, and in practice it performed proportionately more

work.

"It conveyed trains of from 16 to 26 carriages from King's-cross with ease, and on several occasions 25 had been taken and time kept, so that the palling power of the engine was established... As to economy in running, it had been stated that the Great Northern engine took trains of 16 carriages on a consumption of 271b. of coal per mile, including ghting up, &s. In October last the average consumption of fuel, with an average load of 11 carriages, was 231b. per mile-a duty which he did not think could be surpassed-certainly not with coupled engines... The engines seemed to have plenty of wohesion for the size and power of the cylinders, and did not slip more than coupled engines under similar circumstances, and with a slight application of dry and, slipping was entirely prevented."

To many of your readers the foregoing extract will undoubtedly be new, and my own experience of theag engines, when travelling on the G.N. line, is quite in harmony with Mr. Stirling's statements; but I have not space for detailed observations. Should my letter appear to some as an attempt to poff the GN, I may state that nothing of the kind is intended, and I have no interest whatever in the line. On the contrary, as a Midland share holder, I suffer from the sharp competition and excellent service of the Great Northern.

[blocks in formation]

SATURN'S SATELLITES. scale of 60" to the inch, the configuration of the [14898.1-THE following diagram shows, on a satellites at 11h. on Sept. 10. Both Rhea and Titan were then nearly at their greatest western elongation, and the former is evidently the satellite inquired after by "Brickwall," query 34118. Iapetus is not shown, as his place would be beyond the limits of your page. He had his dark cap on at that date, being in the S E. quadrant of his orbit, and was but faintly visible. I happen to have measured his position on the evening in question, and the right, and about 28in. above the centre of the on the same scale as this; he was about 5.5in. to planet.

teura in general, I am indebted for the data on It is needless to say that, in common with amawhich such configurations as these may be founded, to the amazing ephemeris published annually by Mr. Marth, in the Astro. Nachrichten (this year in Nos. 2205-2207), and repeated by him in monthly instalments in the Astronomical Register and the Observatory. In order to give graphic expression to these data, my own plan is to draw the elliptic orbits of the satellites around the ring and planet, and divide them into spaces of one hour each in the lathe, renewing the sketch as often as the change in the apparent orbits is so considerable as to require it, and to mark down from the ephemeris the positions of the satellites whenever there is a probability of observing them.

It is most interesting to realise the unfailing accuracy of Mr. Marth's predictions, and to watch the rapid variation, on the same evening, in the positions of the satellites with respect to one another and to the planet. The five principal satellites can be seen and measured with a 5in. or 6in. refractor (some observers say with 4in.), but it takes a good telescope, of good aperture, with a good eye behind it, and in a good state of the atmosphere to observe-not merely to glimpse-Eaceladus.

[blocks in formation]

S

be additional cylinders if required, all constructed might be necessary where complicated calculations and acting substantially in the same manner; these or large number of rates had to be calculated. To the inner cylinder the pounds, shillings, and pence table is also affixed, and when at work the arms of these cylinders may be brought over one another, thus bringing the slot-ways on the two cylinders even or opposite one another. The arms on the segmental wheels pass through slots formed in the base, and on the edges of the slots the rates per week are placed. The operation value of fifty-four hours at 183. per week, set one of is as follows:-Supposing it is required to find the the arms at 38..per day, when opposite fifty-four Again, suppose the value to be sixty hours at 369. hours will be found indicated 18s., the sum required. per week, bring one (the upper) arm to the end of slot and the other to 36, and opposite 60 the required sum is found.

According to another arrangement, the casing is fitted with only one inner cylinder, in which case the number of rates will be reduced, and one segmental wheel will be sufficient; also by dispensing with the half hours between each hour on the stationary board the space will be reduced by one-half; there fore one cylinder will act in place of two; in all cases the 1,, or , will be at the top, so that it can be added to the total. By this latter arrangement the cost of the machine is considerably reduced.

J. M. P.

TWIST AND RACK WHEELS. [14900.]-"XYLON'S" letter (14575), page 448, July 12, 1878, is more particularly addressed to another reader, but as I have not yet noticed any reference to this subject, I should say there deeper-seated reason than that "Xyloa" has sus pected for the squaring and the extracting of the square root in question, where twist is the subject of calculation.

N

D.

[ocr errors]

Book, Propositions 19 and 20, that "similar recti It is beautifully demonstrated in Euclid's Sixth linear figures are to one another in the duplicate ratio of their homologous sides"-that is, that these figures-meaning the areas of them-are to one another as the squares of their corresponding sides, "The areas of circles are as the squares of their and from this it is an easy step to the following:diameters or their circumferences," and the converee of this is that the "diameters or circumferences are to one another as the square roots of their areas," and this is what may be taken as the foundation of the subject, for the sections of all twisted yarns are circles, or may be considered as such.

The twist in any yarn, or thread, or rope, may be conveniently represented by a right-angled triangle, the other side of this right-angled triangle is the one side of which is the circumference of the yarn, distance measured along the axis of the yarn from one twist to another, and the bypothenuse of this right-angled triangle is the length of the spiral from one twist to another.

A MACHINE FOR CALCULATING WAGES. for calculating purposes may be useful to your [14899.]-THE following description of a machine readers, especially those who have to calculate the wages or incomings and outgoings of a large factory. It is the invention of Mr. H. Porter, jun., of Stockton-on-Tees, who obtained provisional protection at the beginning of the year, but has not secured the seal. His object is to provide a simple and efficient material or length of fibre, and of the same hardIn different-sized yarns made from the same machine specially adapted for calculating wages, but capable of being used as a ready reckoner generally ness or degree of twist, these right-angled triangles for calculating rates of interest, prices of goods, and are all similar to one another, and from this it fol the like purposes. According to one arrangement lows that the twist, or the leogth of yarn it takes an outer cylinder or casing is secured to a suitable to contain one twist, is directly proportional to the box or bed; this cylinder has a slot-way cut length circumference of the yarn, and that the number of wise in same, and on one or both sides of the aperture turns in a given length of the yarn will be inversely of the slot way the hours, half-hours, and quarter proportional to the circumference. The weights of hours if necessary, are marked. Inside the fixed cylinders of a given length and of the same material, cylinder is another cylinder, with slot-way like that are as the areas of the cross sections of these cylin in the fixed cylinder, and of about the same size, ders, and as has been said above, the areas of circles and on or to this cylinder is attached a pounds, are as the squares of their circumferences; or conshillings, and peace table; this cylinder is provided versely, the circumferences are as the square roots with a boss at bottom passing through the base plate, of their areas; it follows that the circumferences are and to the boss a pinion is securely keyed; the pinion as the square roots of the weights. "Counts" is in gear with an internal toothed wheel, which latter or leas vary in two ways, either by is provided with a handle or arm. There is another variable weights for a given length-here, of course, and inner cylinder mounted on a spindle at bottom, they are directly proportional to the weights-or by passing through the boss on which the other cylinder variable lengths to a given weight, llb., and bere is mounted, and resting on cross-bar of the base. they are indirectly proportional to the weights, from This spindle also carries a pinion actuated by internal which it follows that the circumferences are as the segmental wheel similar to that into which the other square roots of the counts directly or indirectly, and pinion gears, and this wheel is also provided with a as has been said above, the twists are directly or handle or arm as in the previous case. There may indirectly as the circumferences; it follows that the

twists are directly or indirectly as the square roots of the counts or leas per pound. As to wheels, "Xylon " seems to be well sware as to how these affect directly or indirectly the weights of yarns or roves, and therefore it will be useless for me to go into this part of the subject. William Meek.

"SELLS."

[14901.]-"PETO" (let. 14820) having perpe trated so very old a pun affords in so doing evidence that he has not long studied either the subject nor the ENGLISH MECHANIC. If he will discard stearine and employ paraffin, use a car fully-fitted lead cap (which is not acted upon by the NH4Cl) instead of the binding screw, he will no longer have an excuse for including himself in the category defined by Dr. Johnson. The writer has had Léclanché cells in constant action upon electric house bells, without attendance for two years.

Search.

STRENGTHENING PIANOFORTE BACK. [14 902.-I HAVE had a cottage piano by a London maker about six years, of very good appearance and brilliant tone in the higher notes, but about two years ago it soon got out of tune in the bass, being regularly tuned every two months. I was puzzled to account for it, as on examination I could not at first detect any fault; but at length, on applying a straight-edge to the frame, I found the

-16x2x

express two of my notes in it, I have used the oldfashioned letters, taking doh to be C) I have omitted all bypharmonics above the VIIIth, as being merely replicates.

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

vibrations.

can

NEW MUSICAL NOTATION. [14904.-I DON'T think I have misunderstood "C. Lark" (let. 14830). I wish I had, but he repeats what he said before. It is incomprehensible how any one who knows the value of the "Modulator No. of defend the printing of music on one dead level. Does "C. Lark mean that the two children he speaks of can sing an exercise from their books as readily as one from the "Modulator ?" If he does I think few teachers' experience will bear his out-certainly mine will not. I have known learners twenty-six and a half years old who could sing from the "Modulator" pretty well, but who would fail when they tried singing from their books.

180

221

20

18

15

12

No. of vibrations.

[ocr errors]

G F

[ocr errors]

C

12

[ocr errors]
[ocr errors]

Ab

Name

No. of Name

of

vibra

of

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

216

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

or C

*Bz or B

A2 F Dz

191 16

[ocr errors]
[ocr errors]
[ocr errors]

12

211

141

VIII. IX. X. XII. XV. *This Bflat is a perfect 5th below F, or a major tone below C, whereas the ordinary Bat is a minor tone below C. It is therefore analogous to rah, and I propose to write it hera B, and rah d.

I think if "C. Lark" refers he will see that when I said "without instruction being able to follow music written in the latter," I was speaking of the "established notation;" at any rate I intended that. Possibly he may think that "statement requires no comment, its very exaggeration being its own refutation," but will he deign to disprove it? I believe it quite possible for one who knew nothing of any notation to follow a simple tune written in the "established" notation. So he could one in sol-fa if it was printed à la " Modulator," because in either case he could see how many notes up or down he had to go, but if it were written in ordinary sol-fa type, it would be an unfathomable riddle.

Dandie Dinmont.

BURNER FOR ELECTRIC LIGHT. [14905.]-I SEND a sketch of my new burner for the electric light. It consists of a glass tube, in. inside and about 10in. long, which is bent to the

[blocks in formation]

back slightly round. I then determined to strengthen the back; this I did by putting in three in. bolts through, as shown in sketch. This at once improved the tone, which now stands and improves after each tuning. a in the sketch is a bevelled washer. Stratford, E.

G. R. K. THE HARMONIC THEORY OF MUSIC. 14903.-As Mr. Jackson seems somewhat glad to find he has made some converts, perhaps you will allow me to say that I have, from the first, fully appreciated all he has written on the subject since May last, and now that he has freely invited eriticism I should like to make a few remarks. Mr. Jackson does not seem to me to have stated the whole case, although he has made the principle clear, and has shown the perfect equality of the major and minor concords. In his table he selects the 20th partial (me), and examines its hypharmonica; but if, when a note (dob) is sounded and all its upper partials are throbbing in the air, each of those upper partials itself generates with more cr less intensity bypharmonics-i.e., sub-tones, itself, if sounded as fundamentals, would, each of itself, have generated the upper partial in question; then we must not select one only of the upper partials (me), but rather try what the whole of then, or, at any rate for the purposes of concords, nch of them as correspond to notes of the scale,

will prove to us.

HE

H

1130

H

shape shown-both arms as close as possible to

gether. A small hole is drilled in the top of the

From this table we get the following major and bent tube to insert two pieces of wire-No. 30 minor concords with perfect 5ths :

From Soh3 FAflatC, CEflatG, AflatCEflat
From te ACE, EGB, CEG

From doh DfiatF, Diat,FAflat, FAflatC From ray EflatGBflat, GBfatD, CEflatG The fruits of this "diharmonic" theory are then the following chromatic scale :-C, Dflat, D (two forms and D, differing by a comma), E, F, G, Aflat, A, Bflat (two forms 8 and Bflat, also differing by a comma), and B. From this scale we get the following chords :-CEG, GBD, harmonic, and FAflatC, CEflatG, AflatCEflat, ACE. EGB, CEG, DatF, DilatFAflat, EflatGBfat, GBfatD, FA, and FAC, bypharmonic.

These comprise all the perfect triads, which can be taken in any key, major or minor, without inducing modulation, as set forth by the best har monists; they further prove the identity for harmonising purposes of the major and minor forms of the same key.

It will be noticed that in this chromatic scale there is no share, and that among the above chords DFsharpA, which is certainly taken as a chromatic concord in the key of C, is absent. The explanation cons to me to be this. DFsharp is not a perfect triad it is merely a portion of the dominant harmony, and consists of the 12th, 15th,

and 18th partials of the dominant; it is in fact a

platinum. Length of platinum wire 14 inside each arm of tube. Two carbon pencils well fitted to tube and 1 in. long, connected on the flat end to a copper wire of No. 12 thickness, are now inserted into the tubes, the points towards the platinum wires, leaving tin. space between the carbon points and the ends of wire. The tube is now warmed, and the air expelled, and quickly sealed and cemented with any fire resisting cement. The two platinum wires are one pole, the two carbon wires the other pole, to be attached to battery or magneto-machine power. The light so obtained is very brilliant, steady, and clear, having many advantages over the two-point carbonburner, and dispenses with the costly regulator. How far the success of the new burner can be estimated is not known, and must be proved by longer experiments; but as at present it is worthy of adop tion and improving in this direction. A bell-shaped globe is better than a round one.

F. E. Fabrig, Electrician, Southampton. AUTOMATIC REED ORGANS. [14906.1-I HAVE obtained an illustrated copy of

the specification of C. Dawson's "Patent Autophon,

or Improved Organ," and forwarded it to the Editor of the ENGLISH MECHANIC, in order that he may give any extracts from it which he may consider of sufficient interest. If R. Smith (p. 656) will favour me with his address I shall have much pleasure in

sending him a complete copy of it. The patent was

I have therefore made oat, on Mr. Jackson's discord, and we are now considering of concords enrolled in 1849 for 14 years, and consequently

principle, a table of the hypharmonics of soh3, te3,
dob, and ray'. (As, however, I know very
only.
little
of the tonic sol fa system of notation, and cannot

September 19.

A. Coates.

expired in 1863. Could not some organ-builder be induced to construct these instruments? I should think they would command a ready sale.

A patent was taken out by Alexander Debain, 29th August, 1846 (No. 11,359), for improvements in pianofortes and other instruments. În the list of abridged specifications the apparatus is termed an "antiphonel," but I think it must be the same to which R. Smith refers as the "piano mécanique." The complete specification, with drawings, may be

obtained from the Patent-office for 1s. 4d., exclusive of postage. George Tommy. 3, Montrose Terrace, Argyle Road, Bristol, September 20.

[Mr. Tommy sends a portion of the drawings belonging to the specification of C. Dawson, No. 12,307, from which it is evident that the latter clearly described the method of sounding organ pipes by allowing the wind to pass through "perforations in a sheet of paper." Hence it would appear that Needham (see p. 514, Vol. XXVII.) has been anticipated.-Ed.]

HOW TO MAKE A LEAD TANK. [14907.J-THE following directions for making a lead tank I take from the Plumber (New York), and if you will give them insertion I think they may be useful to many readers. For a full description of the method of burning joints in lead, I would refer to p. 356, Vol. XII., of the ENGLISH MECHANIC, but an improved burner is now employed, which to a certain extent facilitates an operation that can be only done satisfactorily after many trials.

Plan the cutting of your sheet lead so as to make as short joints as possible; if the tank is to hold water, use good easy flowing solder; if it is to hold acid, burn the seams; if you cannot do this, use very coarse solder, as the acid will act upon it much slower than when the solder is fine.

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

If the tank is very shallow, and long and wide, cut as sketch, and wipe seams in the corners; this will save the seams from A to D and B to C, and the solder saved will more than pay for loss of lead cut out of the corners. If the tank is deep and long, cut the sides, bottom, and lapping for top edges of box of one piece of lead, and the ends of two other pieces; this will make two seams in the corners of the box, one at each end. If the box is small and lead light, and you wish to make joints with copper bolt, put your bottom and sides in one piece falling short 2 inches at each end, instead of allowing the edges to join in corners; then cut your ends, folding in the corners to meet the bottom sheet, dress the edges of lead into a small groove cut in box under where the seam will come, and run the seam with the copper bolt.

[blocks in formation]

Fold corners as shown by dotted lines. B C is the length of end of box, A B and C D the distance the bottom lead falls short of the length of tank at each end. After laying out the pieces of sheet lead as above, multiply length and breadth and weight per square foot, to get the quantity of material. The quantity of solder will vary from 1 to 3 lb. per foot of joints according to the way it is wiped; do not forget to allow enough lead to cover the top edges of the box, and to drop down a inch on the outside, where a row of tinned tacks with large heads should fasten the sheet lead. H. Wells.

REPLIES TO QUERIES.

In their answers, Correspondents are re-self with ordinary (spherical) glasses. Did you really spectfully requested to mention, in each instance, the title and number of the query asked.

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

E

centres for shoulder of broken pivot to run in; E E, drill-holder, which slides through chamfered centre to drill the broken pivot, by pressing the drillholder in with the finger as the pinion is revolving; F, chamber for drills. If "Country Jobber cannot get it after this description, if he will give his address I will tell him where it may be obtained. The sketch given is the exact size of the tool.

AMATEUR.

[33156.]-Cupola.-Possibly you will appreciate the information to be found on page 496 of Journal of Iron and Steel Institute, No. 2, for 1873, relating to melting the metal at the rate of 7 tons per hour for a large anvil block. I have my own ideas on this subject, although I have no practical experience in iron founding. If "Cupola " advertises an address I will make him welcome to my personal views as to how pig iron, in large quantities, may be melted quickly and well with a minimum of fuel, and involving very slight alterations of existing plant. His practical knowledge and experience will readily enable him to decide as to the commercial value of my suggestions.-F. W. S.

[33264.]-Centre of Gravity (U.Q.)-Locomotives are adjusted upon weigh-tables for the special purpose in a weighing shed. - JACK OF ALL TRADES.

[33281.] Parallel Motion (U.Q.) Set the centres of your beam gudgeons level, and centres of parallel rods the same, and square off and distance from centre to centre by lining up.-JACK OF ALL

TRADES.

[ocr errors]

be no difficulty after patient and careful testing in suiting you with a pair of proper glasses. I have no doubt the element of astigmatism enters largely into your case, and hence the difficulty of suiting your. consult two "oculists" or were they only "opticians"-frequently, only "spectacle sellers?" Again, if you consulted oculists, and they were elderly men, they would probably ignore your astigmatism, as it being a very troublesome subject they would not "bother with it," the correction of astigmatism by proper glasses being only achieved by much time and trouble, and it is only of late years that it has been recognised at all as a remediable factor in cases of affection of accommodation and refraction. If "Optic" lives anywhere near Manchester, I would be glad to devote an hour to the elucidation of his case-of course, gratis. Should be care to accept my offer, let him advertise his address, -CYSTICERCUS.

[ocr errors]

[33659.]-Chlorhydric (U.Q.).—I suppose you mean chlorhydric acid. It is more usually termed hydrochloric acid, and is popularly known as "spirits of salt." Its formula is HCI; it is prepared by heating fused salt with dilute sulphuric acid; gaseous HCI comes over, and it is dissolved in water. For further information see any work on chemistry.C. DETAILLE. [33682.] Cleaning and Re-bronzing Old Lamp Stands.-" Glair it" was meant for "not glaze" (see reply 33782). This protects it from the action of the varnish until the varnish is dry. In using the various bronzing powders I have tried different varnishes, and without this protection I find that the varnishes turn them all shades of, green, and from grey to almost black. To leave them without varnish or lacquer is to waste time and labour. I generally use a coat of stone ochre or one of the chromes, according to shade, mixed up with 1 part of japanners' gold size and 2 or 3 parts turps, and give the article a coat of flatting-i.e., a dead, not a glazed surface-and then gold size and powder. It has a much better appearace. Lacquer 1 pint naphtha, 4oz. shellac, and loz. sandarac; put in a bottle, and set aside, shaking it frequently until dissolved. When dissolved pour off the clear, and divide, and thin down with methylated spirit as yon want it. Have two bottles with some methylated or turmeric root for gold or yellow, and some spirit, and in one put some hay saffron or gambogs dragon's blood in the other. By these you may get any grade from copper to gold. This must not be painted on, but as thin and light as you can. The quantity would be enough to make a full quart, lated spirit for dissolving the lac. It disintegrate independent of dregs. Many recommend methy it, and answers very well for polish; but it is not good solvent. With naphtha it will be as clear 25 wine, and little waste.-JACK OF ALL TRADES. of any book treating of the manufacture of tobacco, [33683.]-Tobacco Machinery.-I do not know but being a manufacturer myself I shall be happy to give "Dux" all the information I possibly can if he will describe more fully what he requires.-F. W. E

[33722.]-Line Resistance (U.Q.).—According to Mr. Sprague's invaluable table of copper wires the resistance of lb. No. 36, which if silk-covered will contain about 2,150ft., will be about 356 ohms. If your telegraph wire be No. 8 B.W.G., which is the most ordinary size, the resistance of a mile and half will be 167 ohms, and 101ft. of No. 36 will telegraph wire be the smallest post-office size, No. equal a mile and a half of it in resistance. If yours 11 B.W.G., 191ft. of No. 26 copper will equal li mile of it. Earth resistance is very small. Try how many of your cells will ring the bell through the length of 36 given above.-PLONI ALMONI.

date for a second-class certificate must understand [33758.]-Engineer's Examination.-A candi the first five rules of arithmetic and decimals, and be able to pass a creditable examination as to the [33457.]-Frosted Watch Plates.-Such frosted various constructions of paddle and screw engines appearance is produced by the plates being heated he must understand the barometer, thermometer, and made tolerably hot, and during the process of hydrometer, and salinometer, and the cause of cor gilding aquafortis is applied, which destroys the rosion; he must be able to state the usual remedies even surface of the brass, and when finished leaves for accidents and so on; but there are no "subthe work somewhat granulated.-SECONDS' PRAC-jects," properly so called, unless steam and steam TICAL WATCHMAKER.

[33573.]-Gasholder.-Thanks to " J. T. M." for drawing attention to the above. What is wanted is to know the best material to put between the joints or laps of sheet-iron plates when riveting them, so that the gasholders will be perfectly gas-tight and free from pinholes when finished.-E. FARREL, Gas Manager.

[33602.]-Mildewed Album.-I have found one receipt for taking ont mildew from clothes, which "W. A. R." can try, if he likes, for his album, but I cannot answer for the result. Mix some soft soap with powdered starch, half as much salt, and the juice of a lemon. Lay it on the part with a brush, and let it be exposed day and night till the mildew disappears.-C. C. HAWK.

[ocr errors]

engines form a subject." Get "Ainsley's Manual," published by T. L. Ainsley, South Shields, or at most nautical chart-sellers, and you will have the means of "passing" so far as a book can supply it.

-E. M. K.

[33763.]—Tinting Mechanical Drawings.-I "A. S. B." will look in the back volumes he will find the list of colours and some hints on colouring mechanical drawings. The list of tints has been given several times.-J. M.

young

[33776.]-Cyprus.-The prospect of a fellow with plenty of work in him" is that he would have a great deal of it taken out of him by fever.E. R.

66

[33781.]-Semi-Liquid.-Try glue and glycerine with alum. Guttapercha and asphaltum dissolved [33619.] Gramme Machine (U.Q.). The alcohol, making of these machines is quite out of the reach and so on.-TRY AGAIN. of any one not well up in electrical details, and before you could be assisted it would be necessary to know what light you would want. A machine for 2-horse engine requires about 20816. of wire, and would give a light equal to 700 candles.-OHM. [33639.]-Spectacles.-Your case seems to be one of hypermetropic astigmatism, and there ought to

&c.

[33795.]-Work on Clockmaking. What 'Stylus" did say was: "The only practical work," "Stylus" has the museum and library of the British Horological Institute at his service, in addition to a pretty fair collection of his own, so that he would not be likely to overlook "the admirable work by Sir Edmund Beckett Denison."

[ocr errors]
[ocr errors]

"Stylas" read that work before it was a "work" at
all, and long before it reached the Weale Series, and
has every edition of it since, including the sixth, the
last one issued. Again, there is not, and never was,
3 Sir Edmund Beckett Denison." When the
"Sir was put on the "Denison was cut off.
The "work" began as an article on clocks and
watches, and another on the dipleidoscope, in the
Encyclopadia Britannica about thirty years ago.
It then found its way into the Weale Series in 1850,
and afterwards into " Clocks and Locks" for the
Messrs. Black, of Edinburgh. Its present name [33884]-Polishing Pinion of Watch.-Pinions
is "Clocks, Watches, and Bells," having been re-
-not the arbours-are polished in the following
vised, partly re-written, and greatly enlarged. But manner:-Fix a block of hardish wood in the vice,
it is not a practical work at all; it deals with form a groove across it, in which the pinion can be
scientific principles and their enunciation and placed.
bearing upon horology. It is for the intelligent wedge form, so that it fits into the leaves of the
Prepare an ordinary watch "peg," ent
"practical man "to avail himself of their value and pinion. Procure some cutting redstuff, and when
reduce them to time-keeping machinery. Reid's
"Treatise," on the other hand, supposes the work. mixed with oil cover the pinion with it, and then
polish with the peg. When the roughness has been
man at the bench, surrounded by his tools, and removed rub well with dry redstuff, which will pro-
knowing the use of them. Mr. Reid was not only aduce polish.-SECONDS' PRACTICAL WATCHMAKER.
practical watch and clock-maker, of long and
extensive experience, but also a thoroughly scientific
horologist; hence we can easily understand the close
relationship of his book to the workman. There-
fore, notwithstanding the supercilious remark of
"Kelby"-based, no doubt, on his learned acquaint-
anceship with matters horological "Stylus'
repeats and maintains that the only practical work
is Reid's "Treatise."-STYLUS JUNIOR,

sulphide, will come over undecomposed, and these
are largely present. Two hundred tons of liquor,
on the above calculation, would yield about 20 tons
of sulphate, which would sell for £360 or so. The
above information is equally true for sulphate,
except that it does not need cooling, and the
carbonic, &c., acids are driven up the chimney. On
the way they should pass over the fire, which decom-
poses the sulphuretted hydrogen. I hope the Editor
will pardon the length of my reply. - PLONI
ALMONI.

[33795.]-Work on Clockmaking.-I believe there is no book published to assist "Ratchet Wheel." He will find in the Horological Journal for July of this year an abstract of a lecture upon clockmaking, which, I think, will assist him. SECONDS' PRACTICAL WATCHMAKER. 133800.] Pure White - Flexible White Enamel.-There is no trouble about getting white zine ground in almost colourless oil, bleached on parpose; nor is there any in mixing up flat colour, as" Jack of All Trades" suggests (33800), but flat colour is not enamel.-DANDIE DINMONT.

[33912.]-Lime Juice or Lime Cream.-May I ask Mr. Strathearn to kindly inform me if formula No. 1 is correct, as 1 drachm (60 grains) of borax will not dissolve in loz. of water unless heat be used, in which case a large portion will crystallise out again on cooling ? What is meant by water of borax" in No. 2 ?-DEDALUS.

[33914.]-Paper Slates.-These I have made, and likewise black boards. First coats: Ivory black, 1 of gold size, and 3 of turps, to dry dead; and with the next coat use crushed sound or foundry coke, finely sifted. In using you will find it best to keep It is best to use an excess of turps, to prevent glaze. adding a little turps, as it evaporates very rapidly. Let each coat be thoroughly dry before adding another, and do not plaster it on, but use a moderate covering coat, and cross it every time. These flatting coats seem easy enough, but you are apt to get in a terrible mess with them at times.-JACK

OF ALL TRADES.

[33923.1-Circular Cog Wheels.-Will Charles Davenport kindly give name of firm using the eccentric cog wheels, so that I could write to them about this important question ?-E. R. DALE, Glanvilles Wootton.

(fluorspar) and soda aluminate are the results of the reaction, and water will dissolve the latter. In this solution carbonic acid is conducted (taken from the chimney). Carbonate of soda is formed while alumina precipitates. This is dissolved in sulphuric acid, and as it is free from iron has a great value for dyeing porposes. It is brought to the market in the shape of china-like cakes. The soda solution is treated as usual. The industry was started in Copenhagen, the process being patented to Prof. Julius Thomsen, of that town. A large manufactory, established one mile outside Copenhagen, failed, however, after some ten years' work. It came into the fertilising hands of a company, but in Germany several works exist and thrive, the products being very pure.-ANGLO-DANE.

[33908] Cryolite- The principal use of this mineral is in the manufacture of soda and alumina. An outline of the method of treatment might be interesting to some of your readers. The largest known deposits are in Greenland, at a place called Ivigtuk, on the Arksund Fiord, about mid-way between Julianshaab and Frederickshaab. The largest works using cryolite are at Natrona, about 20 miles from Pittsburg, U.S. The cryolite, on arriving at the works, is carefully picked, and any adhering foreign minerals removed. After drying in an ordinary open furnace it is passed through a Blake's crusher, and then ground between flat stones and bolted. The powdered cryolite is mixed with certain proportions of lime and limestone, and the mixture ground together under edge stones. This mixture is then calcined. As it fluxes very readily, a peculiarlyconstructed furnace is used. In this furnace the cryolite and lime are decomposed into aluminate of calcined mixture is placed in lixiviating tanks, soda and fluoride of calcium. After cooling, the where the soluble aluminate of soda is washed out. This solution is then run into vessels and treated with carbonic acid gas, when hydrate of alumina is precipitated and carbonate of soda left in solution. The hydrate of alumina is then washed and dried, and the carbonate of soda solution run into crystallising vessels.-ZIA.

in oil (Brunswick green it is called) and some black [33974.]-Green Paint.-Get some middle green in oil, and mix a little at the time into the green, until you get the desired shade. A small portion of chrome will give an olive tint.-JACK OF ALL TRADES.

[33802.]-Watchmakers' Societies.-There is Do such society in England as " Watchmaker" seeks. The Horological Society of London does not meet the requirements sought. Although there are several schools of horology on the Continent I am unable to recommend one in preference to another. But I [33931.]-Mercuric Ethide.-I would draw Mr. have no doubt if "Watchmaker" will write to Mr. Woodman's attention to the fact that he has not Lawson, watchmaker, Old Steine, Brighton, Sussex, answered my question on the above. I asked for the [33974.]-Green Paint.-Bronze green paint is that gentleman will give him advice, as he was apparatus required, and he answers that it is in- generally prepared for use by mixing the following educated in the art at one of such schools, at which I Perhaps he was afraid lest I should furnish subject- bright yellow, 4 parts; Venetian red, 2 parts; black, tensely poisonous (which fact I knew very well). colours :-Ordinary Brunswick green, 35 parts; believe he carried off prizes and certificates.SECONDS' PRACTICAL WATCHMAKER. matter for a newspaper paragraph, headed "Melan-1 part. A little more black may be added if not choly Accident." [33303.-Blide-rest Boring or Inside Turn- these matters, I don't expect the above result. The dryers, and turpentine to a proper working consistAs I am not exactly a novice in dark enough. These are mixed up with linseed oil, reason why I wish for a description of the apparatus ency.-H. B. F. is because in the ordinary books on chemistry no mention is made of it. For instance, neither Roscoe, Schorlemmer, Frankland, Armstrong, Bloxam, or even "Watt's Dictionary," Vol. IV., 1866 edition, under Organo-Metallic Bodies (by Frankland), give any particulars of it. If Mr. Woodman, Mr. Clements, or any of our correspondents could give any information on the subject, or give the name of any book which describes the apparatus required for the preparation of the organo-metallic bodies, they would greatly oblige several chemical students, including-H. T.

ing.-Use a tool shaped like diagram.—TELESCOPE

TELE.

[33945.Pythagorean Theorem.-Will yon kindly permit me to correct a mistake I made in my communication last week? I said: "They would then cut the angles of the large square;" the lines would not necessarily do so, but might in some constructions.-R. J. LECKY.

[33827.]-Weaving.-I see that the query on the above is, like all others on weaving, likely to remain unanswered; I therefore take the liberty of giving my small experience in above. Twilled work, such as regattas being of two or more colours, either linen or cotton, are sized or dressed separately, to keep the colours pure and clean, as they ran when wet-that is, the colours run into one another, and if one is blue, and the other white, the blue spoils the purity of the white, and the cloth is not made properly. They have to be warped and sized separately, and when they come to the loom there has to be 2 rods for each colour, and 2 more to keep the yarn either in splitfuls or end for end, and this makes for the blue-and-white regattas 6 rods.-J. BROWN, Belfast. The reason why three-leaf twills are made in 6 beddles is that the yarn, when divided in the beddles, works easier through 6 heddles than 3 do, and is less liable to break. For three leaf drills I never put more than 2 rods and a pair of clips; but doctors differ.-J. N. M.

[33953.]-Magnetising.-Possibly the steel bars
you wish to magnetise are not hard enough to
retain the magnetism. If so, heat red-hot, and
plunge them in cold water; then re-magnetise them.

[338931-Ammonia Direct from Gas Liquor.
-According to promise I will do what I can for
Mr. Ker. What he says about heating liquor in
still until ammonia ceases to come off is quite
correct. The lime can be put in through a pipe,
which may be plugged up when lime is not being
put in. It is well to have a dasher arranged inside,
which can easily be turned by hand a few times now
and then. Heat the still either by steam or fire,
whichever is most convenient. You should have
both your gas and your water kept as cool as possible,
as water will take up much less when warm. The
amount of ammonia in gas liquor at 6° Twaddell
may be taken as about 25 per cent., which for 200
tous would give 5 tons of ammonia gas, or 10 tons of
the saturated solution, or more, according to the
strength. I will now tell you a few of the objections
to this plan. You will probably get into your solu-
tion ammonium carbonate and sulphide, as well as
eranogen compounds and other sulphur products. ALL TRADES.
These are so subtle and insinuating that I have heard [33968.] Cryolite and Rutelite. Cryolite,
that it is next to impossible to free the ammonia found in large quantities at Ivigtut, Greenland,
completely from some of them, and that no one who is used extensively for soda making. 'The ground
wants really pure ammonia will use that obtained mineral is mixed with ground limestone, carefully
from gas liquor. In your solution these impurities mixed and exposed to a heat that will not fuse the
will be largely present, as the carbonate, and perhaps mixture but decompose it. Fluoride of calcium

pot of glue, and to every pound put a good teaspoon
[33955.]-Planing Machine.-Prepare a good
ful of sugar, take loz. of powdered nut galls, and
pour half a pint of boiling water upon them, stand
at the side of the fire for an hour or two, then pour
off the clear and bottle for use, putting a few crumbs
of camphor into the bottle to keep out mildew. A
fourth of this may be mixed with a pound of the hot
glue. Now, if you get some highly-glazed brown or
manilla paper, glue on one side, and glue the
machine, and strike down with a straight edge to
strike all superfluous glue out of joint, and do it
properly, your paper is set as soon as down. Next
glue your bed, or paper and brass, and put a heavy
weight on. Gather up the surplus glue, and clean
round. If your plate is level and you are quick it
will be a good job, and you may plane your plate
down as thin as a piece of paper. With a chislel, very
thin and taper, inserted at the edge, it will part
from the table through the paper very readily, and a
sponge and hot water with a scraper will soon clear
away the other. This can be done upon an iron bed
best, because the wood absorbs the water and pre-
sents a disturbed face, and if ever so truly planed
never falls back in its old position again.-JACK OF

Punch discs of various sizes from leather of suitable [33978.]-Bells Ringing the same Tone.thickness, and with Stephanto's cement (33895) glue one, two, or more pieces on each bell (you need not bother the 21st one) till the sounds satisfy you. This plan will be easier than waxing or filing.

NITRAM.

[33980.]-Brine.-So far as I know, salt-pits or brine is found only in the districts mentioned, in the United Kingdom. It is not found inland on either the east coast of England or in Scotland.-H. B. F.

[33991.]-Soldering Brass Wire.-Lay them upon a block of pumice stone, one at a time, first; then couple up with another in threes, &c. Use borax and fine spelter, with a blowpipe. Mr. Fletcher has given a sketch of a few in this paper, and I believe all are very good.-JACK OF ALL TRADES.

[33995.]-Cement for Cast-iron Tanks.-The best joint for these is the ordinary rust joint, consisting of iron borings well hammered in with a little sal-ammoniac. I have used this in cast-iron tanks, 16x4, in which sometimes hot and sometimes cold with flanged plates bolted together, measuring 32 x liq 1ors were kept, and have found that the expansion of the joints is much the same as that of the tank itself, and holds tight.-H. B. F.

66

[34003.]-G. N. Engines.-Perhaps it may inte rest"Murano" to know that he has been correctly informed respecting the last 4 new G. N. engines, Nos. 516, 517, 548, 519. They all are Sft. single, and have leading bogie wheels with outside cylinders, and are fitted with Smith's vacuum brake. I often see the above engines running over this portion of the G. N. Railway (Doncaster). Perhaps Willesden" would like to know that No. 47 bogie engine often takes the 10 a.m. ex Leeds London express from Leeds to Grantham, and returns to Leeds with the 5.30 p.m. from Grantham. I may add that 519 came out about the end of May, I think. I saw it running in fine style with a heavy train on (the 12.10 noon from York London express) near Retford today (September 20). No. 541 is a coupled engine. The bogie engines which run in this district are Nos. 1, 8, 33, 47, 221, 545 to 549. I suppose No. 61 single inside cylinders, which runs the 10 am. ex King's cross Scotch express from Grantham to York, broke down to-day (September 20), and No. 291, a coupled engine, has taken its place, but the same driver always drives the above Scotch express, and returns with the 3.5 p.m. up Scotch express from York. Nos. 14 and 61 generally run the above express, they have done so now for over 18 months, I think. Can "Murano" kindly answer my queries

[34036.1-Electrical. Wood is preferable to cork. Mount your cylinder on two strong wooden uprights, with holes for the spindle and handle to pass through. Stick the cushion on a piece of wood, to which fix a glass rod; cement the lower end of the rod in a square piece of wood, and let this slide pretty tightly between two pieces of wood on the base of the machine forming a groove. With this mounting the cushion can be removed, and any degree of pressure given. In the diagram, A is the

Nos. 34173 and 34174? I should be glad if he can.- of the usual "composition pedals," which, instead IRON HORSE. of thrusting the stops backwards and forwards, cut [34011.]-Photographic.-As an amateur photo-the wind off certain stops when fixed down, and vice grapher of some little experience, and having tried a versà when released. Four of these pedals govern considerable number of apparatus by various makers, the great and pedal organ; the remaining three I beg most emphatically to recommend for dry plate belong to the swell.-E. BROMELL. work the compact and exceedingly convenient and reliable camera and lens manufactured by our valued correspondent, Mr. W. J. Lancaster, the firm being Messrs. J. Lancaster and Son, Bull-street, Birmingham. Their advertisement appears regularly in "ours." It consists of a bellows camera, taking a view 4 in. x 34in., three dark reversible slides (each holding two plates of the above dimensions), and a telescope stand which, when packed for conveyance, forms a walking-stick. The whole goes into very little compass. I took one with me on my annual excursion this summer with a box containing 3doz, emulsion plates, and got a stock of really excellent negatives. I find that it is appreciated by a large number of professional and amateur photographers, and I have never heard it spoken of except in terms of most unequivocal praise.-MEDICAL PRACTITIONER.

Man"

[ocr errors]

[34015.]-Paste.-The paste An Old Literary came across was probably paste made for shoemakers from rye flour. If he well boils his paste and adds a small portion of sulphate of zinc or the crude white copperas, as it is called at the oilshops (not much called for now as we have patent driers to hand), he will find his paste keep for the twelve months round. I have done so, and with size as well. Not a great while ago I gave a man some size over a twelvemonth old, and he doubted my word, but, as the Yankee would say, it's a fact. A pea or a few crumbs of camphor in a gum bottle or ink will prevent mould.-JACK OF ALL TRAades.

[34015.1-Paste.-I have found that the addition of about two drams of powdered borax to a pint of paste effectually prevents its decomposition.

DEDALUS.

[34026.]-Gas Lighting by Electricity.-In reply to Agricola," Messrs. Motters head and Co., of Manchester, are still able to supply a few of the American patent gas-lighters. They were out of stock for a short time, but have secured a few dozen now. The instruments are no longer manufactured.-BETA.

[34032.]-Organ at Bow and Bromley Institute. This instrument has two keyboards of four octaves and a sixth, from second bass C to second treble A; and a pedal board of two octaves and a half from second bass C to middle G., It comprises twenty-seven speaking stops, arranged thus

[blocks in formation]

B

C

D

[blocks in formation]
[blocks in formation]

[34039.]-Preserved Fruits.-Take, for instance, some plums. Well prick them with a fork, then place them in a pan; pour some water over them, nearly boiling hot, so as to cover them. Let them remain until cold, drain them, put some lump sugar in a stew pan, and to each lb. add a tea-cup of water. Boil it until it reaches 230°, let it stand a short time, them in a stoneware jar), so as to cover them. Next then pour over the plums (having previously put day repeat the operation of boiling the syrup, adding either let them remain in the syrup or drain and dry more sugar; repeat for three or four days, then off in a warm oven.-L. W. D.

8. Combustibles: The chief constituents of all com. bustibles are sulphur and carbon.-ARTHUR S. WOODWARD.

[34044.] Mineralogy." Hereward" should vary the arrangement of his collection. Say, first arrange them according to the crystalline systems to which they belong, then according to their prominent constituents; again, according to their chemical composition, silicates, oxides, sulphates, &c., being placed in separate groups. Allophane is a hydrous silicate of alumina, generally found in chalk and sandstone, mostly yellow or white in colour.K. C. L.

[34016.]-Bicycle.-The method of straightening the rim of the bicycle wheel when out of truth sideways is very simple, though, I believe, not generally known to amateurs. Turn the wheel round, holding a piece of chalk to mark where it is out on both sides, then with a small hand-vice or pliers loosen the spokes on the side it bulges out, and tighten on the opposite till true.-STANLEY ROADSTER.

[34046.]-Bicycle.-Your bicycle is suffering from a complaint general to "Ariels," and one which I should think the makers ought to pay some little attention to. It is caused by the staples in the rim not being placed at equal distances from each other, the result being that the spokes are not all the same length, so that when the lever is tightened some are tighter than others, those that are tight pulling the wheel out of truth. The means by which I turned some wheels is to try all the spokes. Those which are tighter than others should be lengthened by beating them out till they are all of the same tension. This is done by placing a heavy smooth-faced hammer one side the spoke, and with another lighter hammer tap it lightly all over until you get them all to the same tension. This, if done neatly, will not injure the spokes. Slacken the nuts which screw up the lever, having previously marked where the rim was touching, lay the place so marked between two blocks of wood, place another piece on the rim, not to injure it by hammering, and with a light hammer give it a few heavy blows, according to the amount of straightening required, until you see it is as nearly true as possible, screw up the lever, care being taken not to pull the wheel out by screwing too tight, which is a very general fault. Report results. Shall be pleased to give any further JONES. information about "Ariel" or "Tangent."-E. H.

[31047.]-Hardening Buff Leather.-This can or wheat starch, scalded or raw. Any of them easily be done with potatoes boiled to a starch, rice starch, washed out afterwards.-JACK OF ALL TRADES.

[34039.]-Preserved Fruits.-The question is [34048.]-Fuller's Battery.-That "F. R. A. S." vague. Raisins, currants, figs, &c., are preserved should buy one and see would be the first suggestion. whole by exposure to solar heat. Apricots, plums. This battery, which we believe is protected by &c., are preserved by being soaked in a syrup of patent, is a bichromate form, so constructed that sugar and water, then drained, dried in a hot room, the zinc in action is either dissolved in mercury, or and candied in fresh boiled sugar. Any kind of fresh presents a mercurial surface, thus preventing polarıfruit can be preserved by a process of partial cook-sation from impurities contained in the zinc. A rod ing. The fruit is put into bottles, which are filled up with distilled water, corked, and wired down, and then subjected to the action of steam.-GROCER. [34039.]-Preserved Fruits.-Place the fruit, freed from stalks, in wide-mouthed glass bottles or jars, shake well down that as little room as possible may be wasted. Put the bottles, with the mouths open or only very slightly corked, in a cool oven for four or five hours. When the fruit begins to shrivel remove from the oven, and cork quickly and securely, either sealing or tying leather over the corks to ren: der air-tight.-C. LARK.

[34040.]-Domestic Fire-Engine-An engine throwing carbonic acid, such as the "Extincteur," is both small and efficacious, especially in checking a fire at its commencement. It acts on flames much more rapidly than any portable engine throwing merely water could possibly do.-H. R. M.

[34040.]-Domestic Fire-Engine. If "Inquirer" will advertise his address I can furnish him with particulars of a patent portable fire-pump, which will meet his requirements, and is useful for a variety of other purposes-washing windows, walls, fruit trees, carriages, raising water to bath-rooms, or top of a house, &c.-G. C. CROFTS.

[34044.]-Mineralogy. In all the collections of minerals that I have seen the specimens were classed according to their acid radicals-i.e., they were divided into silicates, sulphates, carbonates, &c. Allophane is a bydrated silicate of aluminium. It agrees nearly with the formula, Al2O33SiO25H,O.PRACTICUS.

[34044.]-Mineralogy.-One of the best and most popular arrangements of mineral specimens is that described by Mr. Phillips in his "Elements of Mineralogy." In this system there are eight classes, viz. -1. Earthy minerals: Minerals which contain silex, alumina, and other earths in greater or less quantity, as quartz, opal, garnet, asbestos, &c. 2. Alkaline-earthy minerals: Minerals in which an alkali as well as an earth are found, as mica, fel. spar, talc, &c. 3. Acids: Of acids only three sulphuric, boracic, arsenic--are found in a pure state. 4. Acidiferous earthy minerals: Minerals containing an acid and an earth, as fluor spar, gypsum, meerschaum, &c. 5. Acidiferous alkaline minerals: Minerals which contain an acid and an alkali united, as nitre, common salt. &c. 6. Acidiferous alkaline earthy' minerals: Minerals which contain an acid, an earth, and an alkali in combinanation together, as alum, cryolite, &c. 7. Metals,

of zinc round which is wound a strip of natural rubber from the top to very nearly the bottom of the rod stands in a small quantity of mercury contained in the bottom of a porous cup. Carbon plates and lichromate solution (Bunsen's) complete the arrangement in the usual manner.-SEARCH.

[34049.1-Crystals in Bath. The bath has doubtless been over-iodised, which is very likely to be the case after adding iodide of potassium. The crystals are iodide or nitro-iodide of silver, and a most prolific cause of pin-holes. Remedy: dilute the bath with a measured quantity of distilled water, equal to about one-half its bulk, filter, and add nitrate of silver to make up to original strength. By far the best plan of iodising a new bath is by immersing a coated plate for about half an hour, as by this means supersaturation with iodide of silver is avoided.-DEDALUS.

134051.]-Hens and Eggs.-As the grass run supplies the fowl with green food and animal food (grubs, beetles, &), by supplying them regularly with the above the grass run can be obviated. My fowls are mongrels, with game and Hamburg blood predominant, but I shall go in for Houdans. Any kind of fowl can be kept in confinement except Dorkings.-ANGLO-DANE,

[34052.]-Metal Polishing.-This is done as follows: Get discs of wood from lin. to 6in. diam., glue round the edges thick buff leather (I use old soldiers' belts), fix on lathe spindle, and use with Trent sand or brickdust.-T. B.

[34052.1-Metal Polishing.-Use a leather buff disc, and emery powder. If very deep disc, a scraper or file first. They are sometimes very deep in German silver.-ANGLO-DANE.

[34054.]-Glazed Jars.-Most common potteryware, except stoneware, is glazed with a portion of lead, and I have found the greatest quantity of lead in the glaze used for the common red ware or crocks. Nothing but stoneware or glass should be used for any acid condiment or pickles. -JACK OF ALL

TRADES.

[34055.]-Photographing the Moon-You can obtain photographs of the moon, but there is perbaps more difficulty in your doing so than you may be aware of. In the first place you must have an equatorially-mounted telescope with a driving clock; and, secondly, you must be a good photographer before attempting to obtain photos of the moon. It you will write another query, stating whether you

« ПредишнаНапред »