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MILBURN AND CO.'S APPARATUS FOR DESICCATING GRAINS (Described on page 4.)

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6ft. perpendicular height, with a horizontal pipe of 3in. going off near the top with a descent of 3ft. or so, to serve as a heat-trap. But this should be into a kitchen chimney finally, to ensure the continuous carrying off of all vapour, otherwise this would injure the plants. I is requisite also to have an earthenware vessel on the top of the house, with water always in it, to ensure requisite moisture, or this heat will be found too dry for plants. Great care must also be taken of dust, or the leaves of the plants soon become covered from the cleaning out of the stove.

There is also an item of expense in repair. Though the interior of the stove, lined with fire-brick, will last for years, the sheet-iron piping, the cheapest and easiest heated, will require renewing every three years, at a cost of about 30s. to £2.

Anthracite, or malting coal, should be used, with care not to supply too much air at any one time, or overheating will be the result. This system was used for three years with No. 1708 house, as gas could not be had moderate. Should anyone be desirous personally to inspect and test these particulars of heating by gas, he has only to apply at 21, Park-street, Bath. J. B.

FIG. 1.

TELESCOPIC.-ANSWERS TO QUERIES. face. If now the mirror be spherical, the cords will appear to converge towards each other as they approach SIR-In accordance with "Leo's" request (page the edge of its disc; but when the mirror is truly 58), I give him my method of roughly estimating the parabolic, the cords appear as they really are, perfigure of specula:-Procure an open wooden frame, fectly straight, and equidistant from each other. similar to that of a schoolboy's slate, across which The simplicity of this test speaks for itself; and are to be stretched parallel cords of smooth whipcord, should the operator have a venetian blind to his winor what is better, Violin strings, or catgut, in a simi- dow, that alone would be sufficient, without a test lar manner to a harp. About 6 of these strings will frame, to enable him to form a tolerably correct idea be enough. They should not be more than in. apart, of the figure, providing the room is large enough to and must be exactly equidistant from each other. permit the mirror being placed at a sufficient distance. Next stand the mirror, which is to be inspected on I should say that to give this test its best trial, the any convenient support, with its face opposite a win- eye should be brought as near to the mirror as distinct dow, and at a distance from it rather more than its vision will permit. Any distortion of the parallel radius of curvature, or twice its focal length. Then cords will then be exaggerated just in proportion as incline the mirror slightly, until it reflects the image the lines are magnified; and it preferable, the cords of the observer's head when standing close to the may be only in. apart to bear this amplification. window. In this position then, with the face looking Next in order, I must attend to my "Pupil" (page towards the mirror, hold up the test frame between 590), or else he will think me by this time a forgetful the eye and the mirror, and parallel to it, until the teacher. "Pupil" seems to think "the band suspeninverted image of the cords is seen reflected on its sur- sion the best for such as himself, with blanket to rest

on." I should think so too. He will no doubt find it very comfortable, and will do for better to rest on the blanket himself than trust his mirror there. Blankets are very nice things in their place, but I, for one, have no faith in them as supports for specula (unless, perhaps, when they are small). He should try the method explained on page 604; it will answer perfectly for a 10in. glass, or even larger. The plane for a 10in should not he less than 1in.; 2in. is still better. As to the ordinary plate, I have used a flat cut out of this material for solar observation, and it has shown the rice grain stippling very plainly; but I have not yet tried it on the stars, but believe it would work well. I may add that the cone of rays in a Newtonian, although bent or diverted to an angle of 450, suffers no other alteration beyond a slight diminution of light; the object seen is in the same position, and moves across the field in the same direction, with respect to the observer, as in a refractor.

The foregoing replies will no doubt satisfy "G. C.," on the same page. My mirrors are made of lin. glass.

HORIZONTAL WINDMILL.

wheel C-with the

with which the predictions have been made, from an I do not consider myself accomplished in the art of assumed theory, so far from being the approbrium of silvering glass, although I have produced some very SIR. In reply to "P. P." and Mr. J. Thrower, I beg the "Nautical Almanac," may be its pride. decent films. No doubt scrupulous attention is to state that I should regulate the machine in the fol"F.R.A.S." says, that the use of Damoiseau's tables required to the directions given by Browning, who, I may say, has kindly informed me that the tempera-lowing mauner :-In the first place, I should weight knows that there are none to replace them, and it ture of the room has much to do with the success of the cord A (Fig. 1), which would run over the pulley-ought long since to have been discontinued, but he surely cannot be an insinuation that the "Nautical it. It should be not less than 700, and great care must Almanac" office ought to have computed others, be taken to get the glass perfectly clean. I have found that should better represent the observed phenomena. that after cleaning the glass with nitric acid, an alkaIt is the duty of computers attached to that establish line solution is useful before the final washing with ment to use, and not to form tables. W. E. P. As to the question asked by "Novice," page 606, I am sorry to say I am at a loss to know what he means. I am afraid he is running his head against some imaginary post. Let him read the directions again more W. PURKISS. carefully.

water.

ELECTRIC MACHINES.

FIG. 2

FIC.I

F

E

-B

Weight B, the lat-
ter being light
enough to allow of
the sail swinging
out in a high wind,
as in A, Fig. 2, and
thus permitting the
excess of wind force
to pass by.
Secondly, I should cause the rod D F, Fig. 1, to pivot
at E, E being above the middle point of DF, and EF
consequently longer than
D E. The effect of this
would be, that when the sail
was at or about B (Fig. 2), E F
would swing back and D E
forward, and the whole sail
lie more or less edgeways to
the wind, as in Fig. 3. To
prevent this occurring, how-
ever, in any but heavy gales
or strong gusts of wind, I
should weight it at GG, and
also perhaps have a cord run-
ning from G to K and M (Fig.
2), with a weight attached to

B

A

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SIR,-"Derf Errac," page 657, reminds me of a promise of information as to Carie's improvements in electrical machines on the inductive principle. I have not happened to meet with further particulars than those he gave or referred to, and they are by no means clear and comprehensible; and I have had too much on my hands to make experiments, especially as I feel very doubtful if the matter is of much value. If "D. E." has not the number, he should obtain No. 226, which contains a description of Holtz's machine, on similar principles. I have tried vainly to get a sight of one, but none of the instrument makers appear to think them worth troubling themselves about. In reference to the brown paper machine, I do not think my remark was calculated to raise the querist's hopes unduly, and I quite agree with "DE." in what he says, it would be a very poor investment of time and labour. I expect a great drawback would be the hygroscopic nature of the paper, which is not a 46 As to the very good non-conductor in consequence. ebonite disc, I hope "D. E." will get off better than I did. I ordered a 15in. one, and was charged 178. 6d. for it, though weighing barely 21b., the seller declaring he had to get it from Germany. Flat sheet ebonite, say in. thick, can be got and cut to size without diffi-sented to the wind, and thus culty, and the price is about 38. 6d. per lb., while the cuttings from the square would be valuable for making up other instruments. For an induction machine a much smaller plate would do; and as there is no strain on it, only sufficient thickness is needed for maintaining its form. SIGMA.

HORIZONTAL WINDMILL.

SIR, Seeing that the subject of windmills is being ventilated in your paper, I send you drawings of a horizontal windmill which I have designed, and which may perhaps be useful to some of your readers. Fig. 1 is a horizontal view, and Fig. 2 a view of it as seen from above. The letters are the same in both figures. The sails as shown at A, Fig. 1, are fixed loosely on to the levers, so as to permit the upper half to fall forward until horizontal, as shown at A', when the lever itself keeps it from further depression: neither can it go farther back than a perpendicular position. The sails are not fixed on the levers exactly in the middle, but, as shown at A, Fig. 1, the upper half is larger than the lower. B is a pulley fixed on near the end of each of the levers, round which a cord runs which is fastened to the top of the larger halves of each of the opposite sails. Fig. 2

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shows the position and working of the sails when in operation, the wind blowing in the direction indicated by the arrows. At Al the wind has the greatest power, the sail being in a vertical position. Soon after passing A2 the last pressure of wind on the sail will cause the upper half to fall backward at the same time by means of the cord fetching up the sail at A4 to a vertical position, the wind itself forcing it up immediately it is raised above a level; the opposite sail or the wind indicated as A2 being then in the position shown at A3, the wind has no power at all. The levers can be shortened to suit the power of the wind, as the inner part, being hollow, permits the outer to be pushed into them and fastened with a pin at C. I have made one similar to this on a small scale, which works admirably. I think great power could be obtained by this machine. Next week, with your permission, I will send you drawings of another windmill, by which I think still greater power could be obtained, and which would be admirably adapted for working ship's pumps, as on board ship there is generally plenty of wind at man's disposal, but which is seldom made to perform those duties besides propulsion, which would be the saving of trouble and expense to the owner.

A RUSTIC FROM BERKSHIRE Downs.

FIC.B

A better, but more expensive plan for regulating
the sails at B (Fig. 2) would of course be to have them
made with movable weigh-
ted fans, as in the ordinary
of
patent nils
vertical
mills. They would then
open in a high wind at B,
close at A on the

reverse

side of the sail being pre

cause the cord and weight,
Fig. 1, to come into play.

K

The sails might slip up and down the arms, as this would admit of the leverage being lessened or increased at pleasure. In such a case they must pivot on a tube. If the arms were not very heavy, they might be shortened, if required, by being drawn through the shaft, thus:

Head of Screw or Peg to fasten the Arm to the Shaft.

THE RELATION OF POWER TO APERTURES
IN TELESCOPES.-TO "HUGO."
SIR,-With reference to this subject, I do not think
the explanation of "F.R.A.S." satisfactory. It is
evident, that if the magnifying power of a telescope,
cæteris paribus, be doubled, the image of the object
on the retina will then occupy an area four times as
great, and consequently the intensity of the light must
be reduced to one-fourth; therefore an object glass of
four times the area would be required, ie, of twice
the diameter. From this it will be understood, that
the power to be used must vary directly as the aper-
ture, and not as the area of object-glass, as "Hugo "
supposes.
S. T. PRESTON.

VIOLIN VARNISH.

ENGLISH MECHANIC, sigued "B.," inviting discusSIR, A week or two ago a letter appeared in the sion on the subject of violin varnish; but although it appears to me a subject eminently worthy of attention, and of interest to a considerable number of your readers, " B.'s" letter has not at present elicited any reply. I venture to write this letter in the hope that the subject may be re-opened by attracting the attention of some of your chemical subscribers or others, although they may not themselves be directly interested in the construction of the violin.

The requirements of a good violin varnish are, that it should afford protection to the wood, but at the same time it must not interfere with the vibration of the instrument. All the ordinary varnishes made from gums and resins are quite unsuitable for violins, since they do not allow the wood to vibrate freely. M. Grivel, who professes to have re-discovered the old Cremona varnish, says that not one of the substances used in ordinary varnish is used in compounding it, and that it is a spirit varnish. If this latter assertion is true, it upsets the generally received opinion that the Cremong makers varnished in oil.

There are many who insist that the sole cause of the superiority of the Cremona instruments is the warnish with which they are covered; but although no one who has studied the subject properly will hold this idea, no one will deny that the varnish is of very great importance; and any hints in the MECHANIC would be highly interesting to many.

I cannot answer Mr. Thrower's question as to the
tested.
If Mr. T. makes any
power required for his lathe.
experiments, and would state the results in your
paper, I should be much obliged.

I have never tested the above plan, nor indeed any
other. My model has no regulator. H. ALGAR.
P.S.-Instead of cords and weights, steel springs
might be used to catch the sails. The springs should
of course be strong enough to
resist an ordinary wind, and
weak enough to yield to a
gale. The sails should be
much larger than I have re-
prssented them either in this

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I must apologise if I have at all infringed Mr. Val-
lance's patent, but at present do not understand
very

exactly how far our plans agree. Would Mr. V
kindly send a side view of his mill, with sails and
spring ready for action?

I have never made any use of mine except as a
motive power to a small model raft fitted with paddle
wheels. I thought it possibly might be employed to
force a vessel against the wind. Clumsiness of work-
manship, however, and disproportion between sails
and paddle-wheels prevented my arriving at any
decided opinion on the subject.

I have known my mill revolve with only one sail up, but fancy it would do so only in a high wind, my model being too small and ill-made to adinit of much

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"F.R.A.S." AND THE NAUTICAL ALMANAC.
SIR,-In answer to a query from "Equatoreal," con-
cerning the tables of Jupiter's satellites, that appear
in the "Nautical Almanac," "F.R.A.S." has employed
language which, I think, is susceptible of misconstrue-
tion, as it may be thought to censure the authorities
tbat publish the "National Ephemeris."
The business of the computers of the "Nautical
Almanac," is to accurately deduce certain results from
certain tables, and the predictions concerning the
phenomena of Jupiter's satellites, are in this respect
as accurate as any other part of the work. I will
remind "F.R.A.S.," "that the use of an ephemeris is
not only to enable astronomers to observe certain phe-
nomena, but to enable them to make comparisons be-.
tween the assumed theory and the observed fact, and so
to derive the amount of correction that must be applied
to the elements, to bring the theory in accordance
with the observations; and when the elements of
Jupiter's satellites come to be re-discussed, the dis-
cordances between the predictions and the observa-
vations, will be of the greatest use, and the accuracy

In conclusion, I may suggest a method by which the fitness of a varnish for musical purposes could be Two thin slips of the same wood, and of the per-that is, made to produce the same nodal divisame dimensions, if made to vibrate in the same mansion-will render the same sound. Now, if one of two such rods be covered with the varnish under examination, and then both rods be caused to vibrate again, the effect of the varnish will be at once apparent. If the varnish be bad, the covered rod will give a lower sound than before; but if a varnish could be found that could be applied to the wood without lowering the sound, or, in other words, without interfering with free vibration, the desired result would be obtained.

J. T.

HOW TO MAKE AN ERECT DECLINING
SUNDIAL.

SIR,-I am not about to repeat in this letter what has been offered in a former one, and for those who wish to know what an erect declining sundial is, I will refer them to No. 252 of the ENGLISH MECHANIC, page 460. My object now is to state the method of constructing such a dial by the terrestrial globe, which may be of service to those who prefer doing it this way to working it out by trigonometry and logarithms. All sundials, whatever be the declination of the place, may be made upon the principle of a horizontal dial, if we only know the latitude and longitude of the place to which the declination of the plane answers, for all are constructed for the meridian of some particular country; and in declining dials, the reason of the substiler line being at a certain distance it would be a horizontal dial has the time earlier or from our 12 o'clock line is, because the country where later, according to the declination of the plane. Thus, for instance, we all know that the time in Africa is the Cape of Good Hope it is 12 o'clock at London; later than in London; that when it is 1hr. 16min. at consequently the sun will come to the meridian of any place in that country sooner than here. Suppose the plane on which we construct our dial decline from the N. towards the E. 63°, we shall find by the globe that such a place corresponds to a place near the S. coast of Africa. We must first count 90° from that point on the wooden horizon, which will be 27° from the S. towards the E., and having made a mark on the globe where it touches this point on the wooden horizon, we must bring it to the brazen meridian, and then we shall find its latitude and longitude. We must remember, however, to have the pole elevated to the latitude 51° 30', and the meridian of Greenwich under the brazen meridian. We shall then find the latitude to be 3° 40′ S., and the longitude 33° E. The difference of time, therefore, is 2hr. 12min.; but as it would be very inconvenient to subtract this amount from our dial, we can arrange the hours for the latitude of London in the following way: Keeping the globe elevated, we may pass a thin strip of brass across it graduated to 180°, or a thin tape would answer the purpose-one end of it must be placed on the wooden horizon exactly at the degree of the wall's declination. Thus, we must bring one end of it to 63° from the N. towards the E.; we must then pass it under the brazen meridian across the zenith, which, as the globe is elevated, will be 384° from the Pole,

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the other end we must place at 639 from the S. ds the W.; then there will be a hemisphere ed, and the meridians passing through 150 (not Pason some globes), which the tape cuts will be the par-area. It will be seen by inspection that they are Foblique angles, and their width may be ascertained measuring with the quadrant. They will be found be the following:-XI o'clock, 9° 43'; X. 190; IX, 57 VIII 35° 10 VII, 45° 56'; VI, 65° 15'; V, 43: these will be the morning hours; the afternoon ars, being farther away from the meridian, will be der, namely-I, 110 20; II, 26° 47'; III, 49° 20'; 7.75° 52' when the sun will leave the plane. The eration of the style, and its distance from the 12 clock iine may also be found by the globe, and in rder to make the style parallel to the axis of the world, and point to the N. and S. Poles, we must form right-angled spherical triangle, and this may be done by any meridian passing through a plane just

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TURNING BUNGS WITH A FOOT LATIE SIR-I bought a small foot lathe about a month ago for the sole purpose of turning bungs. The size of it is 31 centre, with a 22 fly wheel. I have spent a considerable amount of time in trying to find out a plan by which I could them (the bungs) speedily, and tried three or four different ways without, I may say, any success. I have no doubt there is a proper method, if I only knew of it, by which I could turn them with great speed, and fear I am only exposing my want of mechanical skill in asking a question which I have no doubt is simple enough to the initiated. I shall be very thankful if you or any of the readers of your valuable journal can tell me of a good plan or instrument by which I can accomplish my object. P. KENNY.

TURRET CLOCK.

W. MATTHEWS, Hill House, Gorleston, Yarmouth.

BREAD MAKING.

SIR, I should feel obliged if any of your readers could give me a good recipe for the making of yeast or barm. It is sometimes difficult to get it from the brewers, even in the country-I mean in remote places, and in London you can't get it all, and if you wish to bake your own bread, you must put up with baking powders. For my own part, I don't believe they are wholesome, and am afraid they leave an injurious deposit on the system, if long used. Besides,

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iron to strengthen the stock and keep the bone to
place, having a transverse pin on which to rest the
instrument, to claw the string back over the bone E.
G, an iron lozenge pin, with two bone pins for sight-
pass each side of stock behind the F transverse pin in
ing. No. 3, the instrument to claw back string HH,
drawing of crossbow. II. two claws put to the
string of bow, when the handle J is drawn back, and
brings the string to shooting position. B No. 2 is a
piece of iron similar to the guard of a carving fork,
and keeps the trigger to place. When this is pushed
forward, the bone A passes round, and the string
thick. The string must be a very strong tendon of an
released, propels the arrow. The bow steel is in.
animal, or bullock twistle. The stock is 2ft. 24in. in
length.
F. B. ARGYLE, Christchurch, Hants.

SIR-Will you kindly allow me to ask Sidney Maddison if he will explain the manner in which the hour and quarter trains of his clock are discharged, and also to explain the winding more fully, and how the motion work is worked. Can the clock be seen in action; if so, where and at what time? the bread made in this way is not light, neither is it tion of mine for preventing those deplorable accidents

COMPENSATION.

POISONOUS POSTAGE STAMPS.

heavy and (no matter what pains you may take in mixing) it is anything but satisfactory. I have tried Liebig's method, Borwick's method, hydrochloric SIR-I went to see a friend of mine one night last failures, and not equal to bread made with brewers acid, carb. amm., carb. soda, &c. but they are really week, and, much to my surprise, found him suffering yeast. from severe vomiting, as he seemed quite well when I is not sufficiently light. Borwick's powders any one Liebig's mode is the best, but still the bread saw him at noon of the same day. I asked the cause can try, as they are sold at many places, and are despatching a quantity of circulars by post that effectual, but for those who are not particular the folof his sickness, and he informed me that he had been panegyrised from day to day. I have found them in evening, and that the gum-or, better, the "glutinous lowing form is perhaps as good as auy, and any perconcoction"-ou the back of the penny stamps had son can make it for next to nothing, the cost being made him very sick. Now is not this too bad? It very trifling; Ground rice, 11b.; carbonate of soda, almost makes one shudder to think what this stuff is 1b.; tartaric acid (crushed very finely), 6oz. To be it must pass down the throats of stamp users. There secured from the air. Use it like other baking powcomposed of; and we know for certain that some of kept in a dry place, in a stoppered bottle, or well are many pretty, patent" little devices for wetting ders. A good sort of yeast is made in Hungary from postage stamps, but how many nse them? We can bran, and I believe the Persians use pease (which are safely say that 99 out of every 10 stamps consumed in the kingdom are wetted with the mouth. The higher priced labels are free from this concoction; so also are the stamps of the Inland Revenue Depart ruent. What excuse has the Postmaster-General for this?-surely not expense, seeing how small the pro

windy) for the same purpo-e, but I am ignorant of the
process. Teetotal barm is made of potatoes, flour,
hops, and brown sugar, quickened, I think, with
brewers' yeast. Cobbett recommends a kind of cake,
made in summer time, of rye flour, but the process,
although satisfactory, is inconvenient.

GUN ACCIDENTS. SIR,-As a humane man, you will, I am sure, insert the following description and drawings of an invenresulting from the unintentional discharge of firearms. Such accidents are almost invariably caused by the cocks becoming caught in hedges, bushes, etc., or full cock, when, of course, any accidental touch on the by the gun being carelessly or ignorantly carried at trigger fires the piece, and the result is frequently wounds or death. My invention is simple, strong, and inexpensive; can be attached to any gun-locks, removes the necessity of always bringing the gun to makes guns much safer, prevents wear of locks, and "half cock" before crossing hedges, walls, etc. merely add that having no pecuniary interest whatever in the invention, and not having patented it, all persons are at liberty to use it. A the cock, with the notches BBB cut or filed on its front edge. C is n steel catch, with a square hole through it, inco which the boss or button D fits. D, a milled boss or button, countersunk at the top to receive a small screw and washer. It has a hole drilled through it to admit a stout steel pin, upon which it turns, and which is rivetted to the lock plate. E is a small, short steel peg, also rivetted to the lock plate, to prevent the catch C from going below the lowest notch B in cocking, and to support the cock if the trigger should be

I

accidentally pulled. FFF are screws to fasten the cover or cap H to the lock plate. K is an ordinary V spring. The notches on the edge of the cock need not be cut quite across the edge of the cock, but the face of the cock can be left unaltered, so that the notches may be unseen. Of course C and D may be made in one piece, if preferred. H is a cap or cover made of stout sheet-iron, case-hardened, or of thin steel. In some locks it will be necessary to place the guard in the rear instead of the front of the cock. In that case it will only be necessary to invert the guard and cut the notches in the rear of the cock. To set the guard, turn the boss D towards the cock, and to throw it out of gear, turn it from it. I have severely tested my invention, and find it never fails. One of the notches B is for full cock, another for half cock, and the upper one is for securing the cock in case it should be accidentally lifted. I sincerely hope that the Baines safety guard may be of service to my countrymen, and that it may be the means of saving human life. HENRY D. BAINES.

DRAWING FOR THE MILLION-No. IV.

SIR, -T. 1 to 4.-Continuation of cylinders and cones. Many figures are combinations of cylinders and cones. Draw always first the enveloping prism, the great outlines. Generalise your exercise, put the solid in other positions: p. ex., horizontally instead of vertically, &c.

vertex.

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in your pages of late. To threw some light on the controversy, I beg to send an extract from an American paper, which has recently been sent to me by a friend on the other side of the water. AN OLD SUBSCRIBER. "During the last few years heating with gas in different ways has been introduced, and doubtless this mode of heating would enjoy a far more extensive application on account of its cleanliness and simplicity, were it not for the high price of illuminating gas on the one hand, and the impracticability of generating gas on the principle of Sieman's gas generator, on a small scale, on the other hand. The supply of a cheap article, seems, therefore, very desirable; and this object, we learn, is about to be realised by the gas works now building at Fürstenwald, near Berlin. The gas is to be generated from lignites at Fürstenwald, about 22 miles from Berlin, and carried to the latter city by means of pipes. For this purpose there will be erected at Fürstenwald 12 buildings, each 105 by 62ft., with an aggregate of 70 furnaces, each containing 10 retorts. The furnaces will be provided with Sieman's regenerator. The gas, after having condensers, is brought to Berlin through a series of been freed from tar, water, &c., by passing through pipes, 4ft. in diameter, into which it is forced by 4 cylinder-blasts of 7ft. 73in diameter and 6ft. stroke. The blasts are propelled by 4 steam engines of 6ft. stroke, and 360 horse power each, capable, however, of working up to 500 horse power. The pressure of the

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U-Cone cut by two planes passing through the V. 1.-Plan and elevation of a square pyramid having two sides of the basis: A D and BC parallel to the vertical plane of projection. V. 2.-The same inclined Draw first the elevation; from S'a perpendicular and from S an horizontal line will give the point S, new horizontal projection of the vertex.

W. 1 and 2.-The same exercise for a cone; the ellipse projection of the basis is limited by the rectangle ABC D. G. QUILOSA.

GAS AS A FUEL. SIR,-I see that the question of gas as a fuel has been more than once inquired about, and written on

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If this composition of the gas can be regularly maintained throughout, it will answer it purpose perfectly. The experiment shows that 3000 cubic feet of the gas are equal in heating power to one ton of lignite, or one-third ton of hard coal. The price at Berlin is rated at 12 cents gold per 1000 cubic feet, and the equivalent of one ton of hard coal will cost in Berlin 1 dol. 12 cents gold. The capacity of the works are calculated at 9,500,000 cubic feet per annum, or about 10 millions per day, which it is said will cover the demand of about half the city."

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The famous temple of Chillambrum, in Southern India (probably at least as old as the Egyptian pyramids), originally consisted of seven lofty walls, six of them within the external one and each within the other, surrounding the central quadrangle. These mids, forming a huge cross, probably by no means the walls had seven gateways and twenty-eight pyraearliest example of that most universally distributed Mr. Mutheran, appear to be far more ancient. The figure, for the crosses discovered in Central India by walls of this temple extended over a mile in one direction, and have never, that I know, been equalled in magnitude by any modern Christian structure. The interior of this temple is decorated by festoons of chains, depending from pilasters; each of these chains was wrought out of a single piece of granite, sixty feet long, the links, twenty in number, having been carved, intersecting each other, and highly polished; indeed they retain their polish to this day. Each link is thirty-two inches diameter, and I am told, only one is broken; and much as I dislike the desecration of ancient monuments, I should like to see a few links of the broken chain in the British Museum, for an example to English mechanics. cannot help thinking it rather doubtful, if our automatic granite working machinery could do much better than these people of the same Aryan race as ourselves did by hand, it is said, without steel toolsbut this I beg leave to doubt-notwithstanding Sir J. Whitworth does deservedly esteem its powers so highly. THE HARMONIOUS BLACKSMITH.

gas in the pipes is intended at 16ft. water, equal to about 71b. to the square inch, since this comparatively high pressure allows of a smaller diameter of the pipes, and seems to offer a lower one in many other respects. The pipes are to be made of in. boiler plates, and not buried, but laid above ground, to render them at any time easily accessible, and supported in an appropriate manner by stone pillars. Under a pressure of 16ft. water, the pipes will deliver 407 cubic feet per second.

At Berlin the gas will be stored in 12 gasometers, each 154ft. in diameter and 40ft. high, having, therefore, a capacity of about 750,000 cubic feet. From these gasometers the city is to be supplied. From experiments made by Dr. Zuirck, of Berlin, it seems that a gas of good heating quality can be made from

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SIR,-In an ancient Peruvian huaca, or catacomb, a syrinx, or Pandean pipe, was found, which was carved out of a solid mass of lapis ollaris. This interesting relict of an ancient and extinct civilisation (which may be as old as the representations of harps found by Bruce in the tombs of the kings of Egypt, an engraving of which is in Burney's "History of Music "), is profusely ornamented with representations of what are termed Maltese crosses, a thing not very surprising when it is considered that the cross is perhaps without exception, the most ancient and widely diffused of existing symbols, both in the Old and New worlds, for it is found throughout Europe, Asia, Africa, America, and even the islands of the Pacific, Tonga, Viti, and Easter Island for instance. This instrument is also ornamented by other symbols, very similar to those found on Egyptian obelisks, and on some of the monoliths met with in Western Europe. An engraving of this remarkable specimen of Pan's pipe, is in the " Trans. Roy. Soc. Edinburgh," Vol. 20, page 121. Query, does not its ornamentation indicate (in common with the almost identity of ancient architectural remains in India, Java, the Pacific Islands, and South America), the intercommunication of the ancient races of mankind, which inhabited the Old and New Worlds, perhaps before the Pacific Ocean was formed, or at least before a large extent of land between Asia and America was submerged? THE HARMONIOUS BLACKSMITH.

LOCK NUT.

SIR,-In our valuable paper for February 25, page 575, there is an account and drawings of a patent lock nut for the joints of railway rails. I think it would be too expensive for railway work, and propose a lock nut for joints of rails in this form; the head of the bolt made to fit in an oval hole, so that it will not turn, and on the inner plate a small square groove, cut across the centre of the hole, aud a cut similar in the squares of the nut, but at the back, so that when the nut is screwed home, any of the squares put opposite the groove in the plate, there remains a square hole for a key to drop in, but not to be made to fit too tight, and long enough to get hold of it to take it out at any time, so that when the plates wear, take out the key and you can either give it a quarter or half turn, whichever it requires to tighten it, so that the nut is level, then put in the small iron key, and it will remain firm until wear takes place. If too expensive for main roads, it would prove valuable for points and crossings in yards, especially for junctions. Let some of our brother correspondents give me their opinion PLATELAYER. of it.

FIG. 3

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KAPPER'S IMPROVED FIRES. SIR,-I send you above a rough sketch of Mr. Kapper's improved fires, which he has introduced into ChatFig. 1 ham Dockyard, with a saving of 50 per cent. is for welding tubes. The sketch shows the working of it. When it welded the shaft tubes for the Glatton the tubes were 13ft long, 4ft. one end, 2ft. 6in. the other. This fire is well adapted for boiler-makers, for welding the inner tubes. Fig. 2 is more for beams, It is plates, or angle iron. It is a very valuable fire. easily lighted or easily cleaned out; there is no turning the work on edge. Fig. 3 is for heating the arms of beams for bending. We are able to bend an arm in one beat. I think the sketch needs no explanation; but if any of the readers wish it, I will be most happy to give it.

GEO. HUART, Franklin-road, New Brompton.

EXTRACTS FROM CORRESPONDENCE.

STARCH.-H. E. Godfrey observes:-"I was delighted with the interest taken in the subject starch. Long live our journal of mutual instruction! Much good might be done among pharmaceutical students by short notes on Materia Medica, Botany,

and Pharmacy, &c."

WATCH CLEANING.-" Ab-oth-Yate" writes:"To Veritas, Stopt, and others. The olive oil purified with lead shavings is very good, but if they will purchase the best almond oil, they will find it much better, as it does not gum nor freeze like the best purified olive oil does. Tried and found good."

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(p. 636) recommends Scru-
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REPLIES TO QUERIES.

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By Hong Kong, 1st class, £263 128.
By Australia,
£257 128.
The duration in time is the same.
Days.

Days. 25

Paris to P. de Galle... 25 | Paris to P. de Galle
P. de Galle to Sydney 24 P. de G. to Hong Kong 15
Sydney to St. Nazaire 55 Hong Kong to S. Nazaire 64
Total

'Screw Loose," or screw [1507.]-SEA VOYAGE.-Seeing that no answer tighter his ideas before he appeared to this query, I extract the following from rushes into print.' The the "Annuaire de la Maison de Melle-lez-Sand," cirforce and real application cumnavigation in 1870. The establishing of the steam of these remarks will be boat lines between Australia and San Francisco (1866), seen by reading further on, and between San Francisco and Hong Kong (1867), has where he says-" Gitche completed the circumnavigation by steam. Manito" is quite right in lines present but a little difference as well as to the saying that the machine price of passage as to the duration of the voyage. used for shoddy manufac- Prices are the following in first-class (I reduce apture is called a "willey," proximatively in English currency), from Paris to or vulgarly a "devil." Marseilles £4, from Marseilles to Alexandria £20 128., Now it so happens that from Alexandria to Suez £2, from Suez to Aden £40, Gitche Manito did not from Aden to Pointe de Galle (Ceylon), £30. At Pointe say anything of the kind. de Galle the two lines separate. On the northern one The expression vulgarly a we pay from Ceylon to Hong Kong £30, from Hong devil was my own! From Kong to San Francisco £60, from San Francisco to this I infer that G. Forrest Saint Nazaire, (France), £70, on the Panama Railway On the southdid not quite understand £5, and from St. Nazaire to Paris £2. what he was writing about; ern line from Point de Galle to Sidney £50, from SydI beg, therefore, to include ney to Panama £60, for Panama Railway £5, from him with those to whom, Colon or Aspinwall to St. Nazaire £44, and from St. Hints to Correspondents' Nazaire to Parls £2. The whole voyage costs:are intended to apply. Gitche Manito,' whose letters are most fully appreciated by me, will, I am see the folly of G. Forrest rushing into print. With regard to G. Quilosa's more respectful letter, I beg to remark that if, after 25 years' experience in teaching, he will inform me through the pages of our MECHANIC that he is not sufficiently up' in the subject of Projection to detect the erroneous teaching in the book he so strongly recommends (Projection,' by Ellis A. Davidson), I will, through the same medium, endeavour to enlighten him, although I have no intention of reviewing the work in question." CONSUMPTION.-" Hanley" states:-"I am glad to see you take so much interest in that terrible complaint consumption. Some years ago, a relation of mine travelled amongst the Portuguese, and the country-people used the following plan for all lung diseases, in the first stage.-New milk one quart, then take a flat bar of clean iron about 14in. thick, make it a bright red colour in the fire, then stir the milk with the iron till you have reduced the quantity by a half a pint; this is taken every morning till the patient gets better; they very seldom give drugs of any kind. Perhaps some of your medical correspondent can enlighten us what is the chemical action of iron and milk on a diseased lung."

MEDICAL OPINION.-"F.R.C.S." writes" to beg to add a further remark on the question of improvement of your journal, and I venture to do so solely on public grounds, it is to caution correspondents, both those who make and those who answer medical questions at various times. I have noticed inquiries and replies calculated to lead to great mischief; I might particularly indicate some relating to the sight and diseases of the eye. I am myself the chief surgeon to one of the large eye hospitals, giving advice to upwards of 10,000 patients annually, but I would not venture to reply to some of the questions as propounded in your columns."

MANGANESE BATTERY.-Mr. W. H. Stone deprecates the imperfect information which has been given since we inserted his detailed account a short time since. He says:-"The strong saline solution,' spoken of in the last number, is best formed of saturated solution of sal-ammoniac. No perforated shelf to hold a supply of salts is needed; at least mine has been working untouched for seven months without. A cylinder of amalgamated zinc open at top and THE USES OF OLD HORSE.-H. E. Godfrey, bottom' is equally needless, as a small flat strip 2in. referring to a letter under this head in our last number broad answers any purpose, and costs much less. says: It may be interesting to some of the readers Lastly, there is no need to give 78, or even 58. for of the ENGLISH MECHANIC who have a passion for each cell. A quart jar costs 6d, a 6in. porous ketchup, to be informed that there are establishments, pot 7d., a carbon to match about 18., zinc about 2d., in and about London, devoted especially to the pre-sal-ammoniac lb 3d, manganese about 1lb. 2d; total paration of genuine mushroom ketchup from old 28. 8d. Of course binding screws and platinum conhorses' livers, which are allowed to decompose for the nections are expensive, but there are simple means of purpose." dispensing with both.

ALGEBRAICAL PROBLEMS.-" Pneuma "says: -"I enclose a reply to a question in last MECHANIC 1or insertion in your next number, if you think it worth while. At the same time, are you not almost too liberal in the space you afford for solutions to algebraic problems, which are frequently of little general interest? Could you not suggest to your readers that almost every young algebraist can surely tind in his own neighbourhood some educated person who would be glad to help him out of an occasional difficulty."

PARAFFIN OILS.-The United States Government has recognized the danger of the so-called paraffin oils. A general order promulgated by the United States War Department provides that hereafter no volatile oils will be issued or used for illuminating purposes at military posts, and all varieties of coal oil will be regarded as volatile. In general, lard oil will be supplied for issues of oil authorised for the necessary illumination of military posts.

ON SKETCHING FROM NATURE.-"Mus " A RARE LENS.-The largest photographic porsays:-"May I make a remark or two on the above trait lens ever made in this country is one of 104in. papers? At line 7 from the bottom the writer says,diameter, recently completed by Ross, and now in the Hence it is always,' &c., &c. He should have possession of Mr. Mayall, of Regent-street. It is an explained that if an appearance of height is to be achromatic lens of great power, and will take porgiven to a building, in the foreground especially, the traits of any size, from the smallest miniature up to perspective must be attended to. For instance, in very nearly life size. It is made of glass of the whitest Fig. 1, standing at the foot of a house, the perspective description, and its size admits so large a volume of -causes the line of the roof to slope as in diagram, and light that photographs covering a space of 10in. by 12in. as the writer himself states and shows, not only the may be done in eight seconds. The lens renders in the proportionate height of the house, but also its posi photograph all that is seen in the optical image, and tion. In the same Fig. we have, on the opposite side his so truthfully that the coarseness and exaggera a smaller house, hence the difference in perspective tion belonging to large photographs taken with The only method we have of showing the stupendous inferior lenses are altogether absent. In the open air height of such towers as St. Peter's at Roine, and <roups of 15 to 20 persons (each face about the size of Strasbourg Cathedral is by the perspective. Proof of sovereign, and the whole picture 24in. by 24in.) can this may be seen in a lithograph of the latter church, be taken with the short exposure of 10 seconds. The by T. M. Richardson, jun." cost of manufacturing the lens was upwards of £200.

Total

104

104

By the opening of the Pacific railroad, the Australian line comes in the second rank. The shortest ronte round the world is that of San Francisco; by this line one can go in 39 days from Liverpool to Hong Kong, and the whole tour requires only 80 days.-CAMILLE, D. P.

[1651.]-LOCKS.-There is a book on this subject, "Construction of Door Locks," to be had of Virtue Brothers and Co., 26, Ivy-lane, Paternoster-row.MATY.

[1729.]-RINGS OF STEAM.-Any force acting suddenly upon the air from a centre imparts to it a rotary motion, which is not only confined to loco's and baccy pipes. If a big gun, on a still day be fired, without shot, with a well greased muzzle, an enormous and regular smoke ring will be the result.MATY.

[1798.]-VARNISH.- Mr. B. Nicoll's address is Regent-c reus, Piccadilly; and his works, No. 11 Arch, Lachmere-grove, Battersea.-A. M.

[1799]-REVERSING ECCENTRIC.-I cannot do better in this instance than quote Rankine :-" To reverse the direction of rotation of the shaft of a steam engine, the piston must be made to come to rest and then to move the reverse way, before completing a stroke, and the eccentric must assume that position relatively to the crank which is proper for working the slide valve when the rotation of the shaft is reversed. That position (or the position of backward gear) is somewhat less than half a circumference from the position of forward gear, measured round the shaft in the direction of forward rotation. To bring the eccentric, therefore, into backward gear, it is sufficient to cause it first to stand still while the shaft nearly finishes the first halt turn backwards, and then to accompany the shaft in its rotation. In most stationary engines, and many marine engines, those objects are effected by having the eccentric loose on the shaft, and so counterpoised, that its centre of gravity shall be in the axis of the shaft, but prevented from turning completely round by means of two shoulders, one of which holds it in the position of forward gear, and the other in that of backward gear, care being taken that the motion of the loose eccentric round the shaft shall be forwards to go from forward into backward gear, and backwards to go from backward into forward gear. To reverse an engine with a loose eccentric, the gab is to be disengaged from its pin and the slide valve moved by hand if necessary. When the shaft has made part of a turn backwards, a stop on the shaft comes against a shoulder of the eccentric causing it to assume its motion, re-engaging the gab and working the valve as before.-MATY.

[1809.]-FEATHERS IN WOOD.-The following which recently appeared in the Builder, will answer

"E. R. S. :-"In the structure of all woods used in

building, there is, firstly, a series of vessels of woody
tissue surrounding the heart of the tree, having a verti
cal growth, and arranged in annual concentric circles;
secondly, there are certain hard woody growths,
called the" medullary rays," radiating from the heart,
and consequently more or less horizontal: these
vertical and horizontal growths are intimately but
regularly plaited and intertwined together, to give
strength to the trunk, and thus fa all is regularity.
Now where the branches burst through the stem this
regular arrangement is upset, and the above-mentioned
woody vessels are disarranged, and pushed at different
angles. When the tree is cut down and sawn hori-
zontally across amongst these branches, these dis-
rupted horizontal and vertical vessels (of different
colours, be it remembered) are seen cut at every con-
ceivable angle, and an ornamental feather,' more or
less extensive, is the consequence.
not exist at the base of the tree, because there are no
branches there to disturb the annual growths of the
wood (minute feathers do indeed exist at the very
heart, and these were caused by the growth of leaves
and twigs when the tree was a seedling or little
cutting). Feathers are not seen in deal, because the
fir is a straight-growing tree, without branches in the
'Feathers
portion of the trunk used in commerce.
are seen most abundantly in 'pollards,' for the simple
reason that after the top of the tree has been sawn off,
an immense growth of branches is always induced,
disturbing the tissues in every imaginable way: the
adds greatly to
action of the light on the feathers
their beauty after the wood is polished."-Gipsy.

These feathers do

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