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useful and industrial arts. That your petitioners have invariably protested against the abolition of these laws, as being suicidal and unjust to the nation, both as regards the protection of property in patents, and the mental acquirements of the honest inventor. That your petitioners sensibly impressed with these views, humbly request that your honourable House will confirm by law the following recommendations, and rectify such other abuses as have been found detrimental to the working of the patent laws.

1. That scientific assessors be appointed to represent mechanical, chemical, and natural science, to assist the judges and law officers of the Crown in deciding patent cases, oppositions, and infringements, so as to render their decisions more certain and in unison with each other, and thereby prevent litigation and uncertainty. 2. That the said assessors be assisted by a competent staff of examiners to report on the novelty of all applications for letters patent, and thus prevent a number of patents being granted for the same invention. 3. That the present system of provisional specifications and six months' protection to be abolished, and in the place thereof a system of registration be adopted at a trifling cost, giving a more extended time, say twelve months, or perfecting inventions before application is made for letters patent, and during the twelve months the inventor to have the power to amend his registration if he finds it necessary. 4. That letters patent shall continue in force, by the payment of an annual tax, for 15 years from the date of the first registration. 5. That a fine be imposed upon any person selling or exposing for sale any article as patented when it is not so, and that the date and number of the patent be affixed to all articles sold as patented where practicable; this would prevent many frauds being practised on the public. 6. That a special judge be appointed for the trial of patent cases, and that on such trials the judge be assisted by the assessors, and all questions of fact, as well as of law, be decided by a judge without a jury. 7. That patents ought not to be granted to importers of foreign inventions. 8. That the granting of licenses shall be compulsory under the approval of the assessors. 9. That the Lord Chancellor shall not be limited to one month only for sealing a patent after the proper time in cases of opposition, and also that he should have power to extend the time for the payment of subsequent taxes in cases of accident or extreme necessity."

USEFUL AND SCIENTIFIC NOTES.

LETTERS TO THE EDITOR.

[We do not hold ourselves responsible for the opinions
of our correspondents. The EDITOR respectfully
requests that all communications should be drawn
up as briefly as possible.]

All communications should be addressed to the
EDITOR of the ENGLISH MECHANIC, 31, Tavistock-
street, Covent Garden, W.C.

All eheques and Post Offee Orders to be made payable to J. PASSMORE EDWARDS.

and Mars in Aries. Uranus is still in Gemini, but will move into the confines of Cancer towards the Autumn.

do not believe that anyone has yet picked up D'Arrest's With regard to the queries of “ H. A. C." (p.190), I Comet; or, at all events, has made any announcement of having done so. If it be visible, it is the only one, great or small, in the night sky at this present writing. In the Supplement to the "Nautical Almanac" will be found Ephemerides of Ceres, Pallas, Juno, Vesta and Astræs for every tenth day during the year; and during certain months for every second day at Transit. Your correspondent's query as to the apparent diameter of the various members of the Solar system in inches, is a really senseless one. Accepting, however, I would have every one write what he knows, and with the ordinary works on Optics, 10in. as the as much as he knows, but no more; and that not in standard of distinct vision, all he has to do is to take this only, but in all other subjects: For such a per- of Natural Tangents, and multiply these by 10. For exout the tangents of the angular diameters from a table son may have some particular knowledge and experience of the nature of such a person or such a foun- ample, suppose the Sun's apparent diameter to be 33, what is its apparent size in inches? Turning to our tain, that, as to other things, knows no more than what everybody does, and yet to keep a clutter with table we find the Natural tangent of 32 to be 0093087, this little pittance of his, will undertake to write the of the radius, whatever that may be, and multiwhole body of physicks: a vice from whence great in-plying this by 10, we shall at once obtain this conveniences derive their original.-Montaigne's result, that the Sun is apparently 093in. in dinmeter. So that if we cut out a little disc of paper 0·1in in diameter, and place it 10in. from the eye it will just cover the Sun. Venus at present, measured in the same way, will appear only 00007in. across; and so on. All this, nevertheless, as I pointed out in answering a cognate question some two or three weeks ago. has little or no meaning, but it is the only reply of demand is susceptible. which "H. A. C's

Essays

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SIR, My knowledge of the views of Mr. Williams
with reference to the Fuel of the Sun" is wholly de-
rived from the letter of "The Harmonious Black
work there contained, I should say that it consisted
on p. 160. Judging from the précis of the
of a little Laplace, a trifle of Mayer some Proctor,
and a good deal of Sir William Thomson; the whole
simmered together and (as the Cookery books say)
served up hot " with Williams.
It is extremely hard to pronounce any opinion upon
an hypothesis-or rather upon hypotheses-coming
before one in such a form; but certainly a ditculty
or two suggests itself to my mind in perusing the ab-
stract of Mr. W.'s book which "The Harmonius
Blacksmith has inade. And firstly, it is perfectly
easy to conceive that the attractive power of the Sun
should cause the descent on to his surface of any
amount of cosmical matter (call such matter plane-
toids, aurolites, or what you will) which comes within
the sphere of such attraction. The mass of the
body or bodies so attracted, being assumed or known,
and their velocity on reaching the Sun's surface, also
determined, the amount of heat generated by their im-
pact becomes a matter of relatively simple calculation.
Well, but then, how does the Sun" leave behind him,
Confining ourselves to one single fragment of this
what is termedin Mr. W.'s book, his "Exhausted fuel?"
effete matter, say a globe of it ift. in diameter, can
we conceive any force which is capable of projecting
it vertically from the surface of the Sun (whose mass
is, bear in mind, some 317,000 times that of the Earth) to
a sufficient height to place it sensibly beyond his at-
tractive power? Were such globe shot off tangenti-
the ratio between the force of propulsion and that of
ally, one of two things must happen, dependent upon
gravitation. Either our assumed particle would de-
scribe a parabola, and fall on to the Sun's Surface
again; or, if it were projected with sufficient velocity
to carry it once round the globe of the Sun, it would
go on describing that orbit ad inifinitum-or until some
fresh force came into operation to deflect it from it.
At all events it would become permanently attached
to the Sun, either as a part of his own Globe, or as a
body circulating round him. This is my difficulty about
the leaving behind" hypothesis. Then, again, I
confess, that, in common with "The Harmonious
Blacksmith," I utterly fail to see why the Sun should
be held to be the parent of the Asteroids, and only,
so to speak, the father-in-law of the other members of
the system of which he is the great centre. (Here we
lose the flavour of Laplace, and detect a very pro-
nounced one of Williams.) Nay, I go farther than
your correspondent; and would ask, why, if we as-
sume the various planets to be portions of the primal
matter of our system; and, to use a very homely
simile, flirted off the Sun during his original process
of condensation from nebulous matter, like water off
a mop; why, I say, may we not credit the various
planets with the production of their respective satel-
lites in the same way? There is certainly nothing in
observed appearances to militate against this idea.
Then again the invitation to believe in the existence
of aqueous vapour, &c.," in "interplanetary space'
seems to make an extraordinary demand on our credu-
lity. Certainly its tensiou cannot be very great with
a temperature according to Hopkins of-3703 Fahren-
heit, and of Fourier of-59° Fahrenheit! It is, how-
ever, a little idle to argue on a large proportion of such
assertions as Mr. Williams's books appears to contain,
for the simple reason that they are neither susceptible
of proof nor disproof. If a man were to tell me that the
inhabitants of Mars had nothing to read but Tup-
per's Proverbial Philosophy," I could not contradict
him. I could obviously only answer that, if so, I
pitied them from the bottom of my heart.
I am rather afraid that there is no single work con-
attaining the information asked for by Mr. D. Jenkins
(2659) p. 166, in an available form. Denison's capital
book, Astronomy without Mathematics," has a table
of the data Mr. J. requires; but this does not include
the elements of the individual asteroids. It is a 4s.
book published by the Christian Knowledge Society.
"Loomis's Treatise on Astronomy," another most
interesting book, published (at, I think, about Ss.) by
Harper Brothers, of New York, contains somewhat ex-
tensive tables of the elements of Solar system, in-
cluding ninety of the planetoids; but, wherever
quantities are given is miles, they are calculated on
the old, and certainly erroneous, Solar parallax of
of 8:58. It has, by-the-bye, just struck me as possible
that Mr. J. Norman Lockyer's" Elementary Lessons
in Astronomy," price 58. 6d., Macmillan and Co., will
be found to have what your correspondent wants, in
it; but as I do not possess the book itself, I cannot
assert positively that it does so.

ARTIFICIAL PRODUCTION OF ICE IN INDIA-Dr. Janssen relates that, in many parts of the Indian Continent, the natives dig shallow pits in such localities which are quite freely open to the sky, and distant from trees, The pitsfare lined with straw, and upon the straw are placed dishes (made of a very porous earthenware) filled with water. During the calm and clear nights prevailing during the period from November to the end of February, the water placed in the dishes freezes, yielding a solid cake of ice, while the temperature of the air is + 10. Dr. Janssen has investigated this curious subject experimentally, and has found that the freezing is principally due to the radiation during the night; but the evaporation of the water, aided by the porosity of the earthenware employed, is not to be overlooked, at the same time.

MACHINE FOR PEELING POTATOES.-The Rev. Liévin Bouteca.-The author (Director of the Convent of St. Joseph-de-Notre-Dame-de-la-Trappe, at Forges (Hainaut, Belgium), has contrived a machine, by the aid of which one man can peel, without very hard work, from 250 to 450 kilos. of potatoes in a hour's time. After the tubers have been first roughly washed, they are placed in a cylinder pierced with holes in such a manner as to form a rasp; the bottom of this cylinder is made movable, and also pierced with holes, as just stated. Motion is imparted to the bottom of the cylinder by suitable means; and, by this means, the potatoes, by the friction against each other and the rasps, are rapidly peeled, while a jet of water is the same time applied to wash the peelings down. GOLD COINS-These were first issued in France, by Clovis, A.D. 489. About the same time they were issued in Spain, by Amabric, the Gothic king. In both countries they were called trienties. They were first issued in England in 1257, in the shape of a penny, of the value of 20d.; only two specimens have come down to us. Florins were next issued, in 1344, of the value of 6s. The noble followed next, of the value of 68 8d.; being stamped with a rose, it was called the rose noble. Angels, of the same value as the latter, were issued in 1465. The royal followed next, in 1466, of the value of 10s. Then came the sovereign of 20s.. in 1489. The gold crown, of the value of 10s., fellowed in 1527. Unites and lions were issued in 1603, and exurgats in 1634 The guinea was first issued in 1663, of Guinea gold. In 1733, all the gold coins (except the guinea) were called in, and forbidden to circulate. The present sovereign was first issued in 1817. The Ameriean half-eagle was first issued in 1793.

I need only refer "R. P. D.," (p. 186), to p. 159.
I may tell Secundum Naturam," that on the 20th
of May, Saturn is on the N. W. boundary of Sagittarius;

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"Salopian" (3749), same page, appears to be a little vague in his notions as to the centrifugal tendency of bodies on the Earth's surface. The centrifugal "force" (as it is called) varies as the square of the

velocity of the body, and in the inverse ratio of the
distance from the centre. At the earth's equator
this is by no means an inappreciable quantity; as a
standing on one of the Earth's poles had merely
very little reflection will show that while a man
turned once round, another on the equator will have
flown through some 25,000 miles. As every particle
at the equator, then, is travelling round at the rate of
appreciable; in fact a body transferred from the
pole to the equator loses something like
part of its weight from this cause alone. If we assume
the Earth, then, to have been in a plastic state it is easy

more than 1000 miles an hour, this effect becomes very

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to see how it would be, so to speak, squeezed out
where the pressure was least. Were the rotation of
our globe to increase about seventeen fold,
its surface at the
equator, would fly off.
everything merely resting on

A FELLOW OF THE ROYAL ASTRONOMICAL SOCIETY.

THE TELESCOPE. SIR,-It happened that some time since, two different friends whom I recommended to go to Slater, of

136, Euston-road, London, each complained to me that he could get nothing whatever done by that optician; and that he had written and waited, waited and written for what he had ordered, ineffectually, and in vain. Speaking, then, of Slater, on p. 130, I applied the epithet" dilatory" to him. I have just learned from one of the gentlemen referred to, that he now finds out that Slater was seriously ill at the time of which I have spoken. This being the case, I feel that I was scarcely justified in using the word I did, to describe a man who was, as it now seems, sick, and physically incapacitated at the time from doing any work; the more especially as I never saw Slater in my life. nor have ever had any communication, oral or literal, with him. Without, then, waiting for any disclaimer on his part, I will ask my querist, Mr.Baguley, to erase the words "were he a little less dilatory," as applied to Slater, and to read the sentence in which they occur straight on without them.

"Ignoramus 2" (2658), p. 166, can have an object glass of longer focus, and consequently higher maguifying powers adapted to his present telescope; but this will involve a corresponding lengthening of the tube. "The other glasses in the inside" form the eyepiece, and could be used with any object glass.

so. If Mr. Vivian after this admission will condescend

As "Neptune" gave no data whatever for the computation of the curves of his object glass, save the focus of his crown lens, and that of the whole combination, I regarded Mr. Vivian's reply as an absurd one; and (believing that, like many other people, he thought that he had nothing to do but to take out the quantities by inspection from Herschel's table) attempted, not very dexterously I must admit, to "chaff" him. I see, however, by his letter on p. 182, that he really does know something of the subject, and must express my regret for having done to take my advice, though, I would commend Coddington's formula to him in preference to Herschel's, as being, I think, more manageable. Mr. V. is probably familiar with the Treatise on the Reflection and Refraction of Light." It was published at Cambridge some forty years ago. I am a little amused at your correspondent's idea that because a man, of necessity, has a good many "rather long computations" to make, it is only reasonable to expect him voluntarily to undertake more.

I may just tell Mr. Baguley, p. 185, that his resolution of Virginus with the power he specifies does not prove much one way or another.

Mr. S. T. Preston, p. 185, apparently proceeds on the assumption that all opera glasses give a power of two diameters only; au assertion to which (with a glass magnifying four diameters now before me) I demur. Of course, in the Galilean telescope, the distance between the glasses is the difference of their focal lengths, and the magnifying power is obviously the ratio of these focal lengths; so that the focus of the eye glass enters as an element into the calculation. The shorter such focus is, the farther from the object glass will the lens be placed, and the narrower cousequently that part of the cone of rays from the objective which it intercepts. Nevertheless, your correpondent is perfectly correct in his assertion that

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their is a practically useful limit, very soon reached, to the aperture of the Galilean form of instrument.

At the request of Mr. R. G. Anderson (3712), p. 189, I have turned back to the volume and page of our magazine which he specifies, and can only say that his method appears to me to be capable of affording results at least as correct as those obtained by the method of measuring courses of bricks, &c.. and that where, as in his first case, an image of the whole solar disc could be made to coincide accurately with a circle of known diameter, at a carefully determined distance from the place where the rays from the object glass cross, I should expect to obtain a very good determination. In his second more complicated case, I should not be quite so hopeful of the ultimate practical result.

Myself a mere Amateur, I should prefer that some working optician should answer "Dioptrics" (3713), p. 189, but I may just say that I never in my life heard of grinding a lens on a glass tool. In the case of my sole attempt in object glass making, 1 first computed the curves, and then made my own brass tools in the lathe. These latter were about half an inch greater in diameter than my intended lens. I do not think that iron would come up to a sufficiently fine surface. I can get quite a semi-polish on a lens by the aid of fine flour emery alone, and the brass tool itself, and when it has arrived at this stage it may be transferred straight to the polisher. I was once told, as a great favour, that Alpaca was the best material to construct the polisher of. Putty powder and rouge are the polishing materials.

-I may tell "H. A. C." (3571), p. 190, that I rather question the power of an 8.5in. reflector to divide μ Boötis at all just now, if Secchi's last measures of it are to be trusted; but that, as soon as the distance of the components exceeds 05, any power over 200 ought to divorce them. I must add that I have not looked at this star for a long time with any instrument which has a ghest of a chance of separating, or even elongating it, and that therefore my reply is a purely theoretical one.

A FELLOW OF THE ROYAL ASTRONOMICAL SOCIETY.

COTTON SPINNING.

SIR. Your correspondent, E. Halmshaw, page 183, asks a very reasonable question, when, in reply to "B. W, R.," he asks the object of some jack frames being made for the bobbin to lead, and others for the flyer to lead, if it is immaterial. The result of the bobbin leading has not any effect on the thread, as E. Halmsley supposes. Having frames of both kinds, 1 will just state my experience with them, and my brother Cottonians can draw their own conclusions. The advantage arising from the bobbin leading, can soon be proved as follows. Break down an end from

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two frames, one of each kind, and let the frames continue running, and you will find the frame where the flyer leads, making the roving into waste, whereas the frame where the bobbins lead, will not make any waste at all; to those that have not the means to try this practical test, the enclosed sketch will explain all that is required. So much for the advantage. Of course there may be more, and perhaps even greater advantages than this, but if there is, unprejudiced

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are merely types of a class which will always exist. Suppose 'Parallax' does unsettle the minds of many people who have not studied the subject, what then? It serves them right for leaving the subject unstudied." I think the closing, part of this statement ought to have been qualified. It doubtless does serve those persons right who have had opportunities of acquiring the kind of knowledge in question, and have neglected. to do so. But Mr. Proctor must. be a very young man not to know that there are thousands who have not had such means at their disposal, but who are very anxious to be set right, not only upon the subject of astronomy. but upon other departments of knowledge; and to do so is, I conceive, a duty incumbent upon all those who have time and ability. While I should be one of the first to denounce captious objections and frivolous questions, it would give me pleasure to hear, and, were I able, to answer the objections of the inquirer upon any subject. If it be desirable to enlighten men's minds upon the constitution of the universe by books and lectures, it surely cannot be thought unnecessary to meet the objector, or remove the doubts of the wavering. And for what purpose did Mr. P. write those admirable papers on The Earth, its Figure and Motions," published in the ENGLISH Co., and to settle the minds of those whom that gentleMECHANIC, but to upset the notions of "Parallax " and man had unsettled? In reading those papers, one could scarcely draw any other conclusion, especially as Mr. P. mentions such persons several times therein. J. DYER, Brunswick House, Tanner's Hill, New Cross..

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trials and close observance, have failed to make them known to me. Now for the disadvantages. 1st. You can drive your frame at a greater speed when the flyer leads. If there is any doubt about it, let any one try to start a frame with the bobbins leading, and the spindles running 900 per minute. 2nd. It is evident that to run any part of a machine faster than is required, and only get the same weight made that you would if you run it slower, is a disadvantage. Extra wear, tear, power, and oil, are the results. 3rd. The "tenter" has to use her left hand in piecing working the lenses into form, and mounting them ing, also that some given by him are omitted. I do

the ends up. This is the sum and substance of my experience-I prefer the "horse before the cart," or the flyers to lead. Can any of your correspondents furnish me with a recipe for making size for the bottom of cops? I have tried several different mixtures, but I cannot get anything to act to my fancy. I shall be glad to receive any reply. HARMONIOUS COTTON SPINNER.

SIR, I am greatly obliged to E. Slater for his explanation of the weights used in cotton spinning. I have been very much puzzled with a roving table, in Alexander Kennedy's "Cotton Spinner," second edition, page 118, and by it I have been misled. also feel obliged for the very good explanation of the cone, and the sun and planet motion. I am sure your paper must circulate in Lancashire, if you can get such correspondents to continue their labours. I am very anxious to understand the baking off motion of a self-acting mule, and also the operation of the cam shaft. I find when the carriage is at full stretch, the rim pulley reverses about a quarter round, but I cannot find the moving power or connection with the driving pulley. Will some one explain them?

EDWARD HABERGHAM.

The object glass of short focus, the rays intercepted before they reach a focus by a double concave lens, of such a curve as to transmit the rays parallel, or very gradually converging, and then a suitable eyepiece, thus?

It appears to me that this construction would obviate the difficulty experienced in grinding object glasses of long foci.

HERBERT.

MR. PROCTOR AND MR. DYER. SIR, Mr. Proctor says: "Mr. Dyer must be a very young man not to know that Parallax' and Co.

not pretend to explain this except by supposing that we devoted our attention more especially to the right. side of the field. The powers used were 90 and 200. If we had been able to compare our sketches with that. by F.R.A.S." at the time, I have no doubt that the omissions would have been supplied.

ARTHUR W. BLACKLOCK, 32, Old Steyne, Brighton P.S.-In reply to James Gray, p. 164, I am unable to tell him whether glass discs, suitable for specula, can be obtained in Aberdeen; I do not think they can, but should think that Glasgow was a much more likely place. I will send a description of the method I have adopted for supporting my speculum, but I am not. quite satisfied with it at present. As soon as I can get to work with it again, in June or July, I hope to improve it.

IMPROVEMENTS IN GUNPOWDER. SIR,-The problem how to project shot from great. guns with the received velocity without subjecting the gun to dangerous strains, has engaged the attention of artillerists ever since cannon have been in use; but until lately but little progress has been made towards its solution. The ranges have indeed been enormously increased; but this has been done

1

MAY 20, 1870.J

by using high charges of quick-burning powder, and proportionably increasing the strength of guns, rather than by a more gradual evolution of the force which impels the shot.

Ancient artillerists employed low-burning powder, something like our rocket composition, and when they wanted to increase the range they added to the length of the gun, so that a larger quantity of their powder might be burued and converted into gas before the shot The Egyptian was expelled from its chase.

bronze piece, at the Horse Guards, and Queen Elizabeth's Pocket Pistol, at Dover, are examples of the carrying out of this idea, and I doubt not that what in those times were considered long ranges were obtained, for they did the right thing, inasmuch as the pressure of the gases evolved must have gone on increasing, until the shot had travelled a long way towards the muzzle, even if it did not increase until the shot arrived there.

Modern artillerists have done just the contrary thing. Instead of adding to the lengthwhich makes guns extremely unwieldy and inconvenient to load at the muzzle-they added to their thickness, especially at the breach, and employed powder which burned so rapidly that the shot was expelled with the required So far as velocity from a short, heavy gun.

regards mere range, one system seems as good as the other, and although I have classed as modern the short, thick guns-whose hinder parts are similarly proportioned to those of the heavy-sterned Christians, which the old divine wrote what he termed a shore to expedite the progress towards future bliss-this must be taken cum grano salis, for the bronze gun at Bhurtpore is almost as well proportioned as a modern brass field piece, and, as a specimen of ornamental founder's art, it would be difficult to surpass it, although the casting is far from sound. Its length is 16ft. 4in., diameter at breach, 3ft. 3in.-See Robert Mallet's work "On the Construction of Artillery."

Probably modern artillerists have carried the reinforcement of the breach to its greatest useful extent, and the Dahlgren guns in th American service, which resemble huge soda water bottles in form, are perhaps the strongest cast iron guns yet made, but, as every engineer well knows, there is a practical limit to the additional strength which can be obtained by mere addition to the mass of a gun, for when the diameter is very great, the interior cools so slowly that there is considerable danger of the material giving way under comparatively slight strains, from the fact that the irregular shrinkage tends to outer parts. separate the inner from the

Hence the advantage of building up guns in successive layers; and this also enables us to employ tough wrought instead of brittle

cast iron.

The repeated failures of heavy cast iron guns induced a 'cute Yankee to revert to the principle of gradual evolution of force, which he carried out by making lateral powder chambers communicating with the chase of the gun. These lateral chambers were charged with powder, and each charge was successively ignited (after the projectile had passed it) on its way towards the muzzle. This is employing many charges of quick-burning powder to do the same work that one large charge of slowburning powder does equally well without the inconvenience and loss of strength which must result from making and loading many powder chambers. Like slow-burning powder, it prevents the gun from being subjected to sudden destructive strains, but the invention certainly does not resemble its inventor in being simple.

Gunpowder being only a mechanical mixture, and unlike gun cotton, and most other explosive substances, a chemical compound, it is not subject to the law of definite proportions in other words, we can use any proportion of; its ingredients we find most suitable for the especial work we want it to do. In addition to the command this fact gives us over the rate of its combustion, we can further modify that rate by varying the size and form of its grains. When reduced to dust it cannot be made to explode at all uuless the mass be sufficiently heated for ignition throughout; lighted at the surface it only fizzes, as every schoolboy knows. As we increase the size of its particles, so do we afford more room for flame to be propagated between them, and the more rapidly is the mass burned and converted into gas, which is only saying, in other words, it explodes, for explosion differs from combustion only in the rapidity with which its products are evolved; but this must be taken cum grano, for it is obvious that if instead of being made into grains it were in one mass, it could only burn at its surface, and would be very slow burning stuff-we can hardly call such masses powder.

As usual, success is only to be achieved by compromise, and the practical problem is, to find the proper size of the grains so that they shall burn rapidly enough to induce a constantly-increasing pressure in the chase of the gun, while the shot travels along it without causing a very sudden and intense pressure before the inertia of the shot is overcome and its motion commenced. When we can make gunpowder which will not only begin to move the shot slowly, but communicate a sufficiently accelerated velocity to it during its progress towards the muzzle of the gun to expel it at the required velocity, the problem of long ranges from light guns will be solved. From the report of some late experiments at Shoeburyness on different kinds of powder, it is evident that that problem, if not yet quite solved, is near its solution.

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The range of a projectile, cæteris paribus, depends on the velocity with which it leaves the gun, and when the force which impels it is gradually increased during its progress along the chase, it would appear that its greatest velocity-i.e. that with which it quits the gun, may be greatly increased beyond anything which can safely be obtained when, as usual, the pressure of the gases is greatest before the shot has travelled halfway along the chase. In the latter case, that pressure acts on the shot much as a bow acts on an arrow-i.e. it drives it with the greatest force at first, and with a constantly diminishing force until it ceases to act; it kicks the projectile instead of impelling it with increasing velocity; but whether it makes the gun kick also is doubtful. Probably the total recoil, if less sudden, would be rather greater in amount if the force be evolved gradually, and continually increases in intensity; for, from the same causes which will give a longer range forward to the projectile, we may expect a somewhat longer range backward of the gun-i.e., increased recoil-for the inertia of its mass would be more gradually overcome, and the force which causes it to recoil continually increase during the passage of the shot along the chase.

serious soberness. The minds of these not very philo-
sophical sceptics, who assume they know all Nature's
possibilities, seem to the unlearned Blacksmith, in
relation to this subject, to be very like those of the
blind and deaf in relation to the phenomena of light,
colour, and sound. The said Blacksmith supposes he
must "grin and bear it; " in fact, he is used to it.
Having been blessed by Providence with a rather
broad back, and being, as regards ridicule, a pachy-
derm, he can well afford the sneerers should have
their enjoyment-like Dickens' good natured coal-
heaver, whose wife "wopped"-"it pleases she and
don't hurt I." and if my queries elicit useful infor-
mation, their purpose will be fulfilled, however much
ridicule the questioner may be called on to bear;
moreover, if it will afford any additional gratification
to the sneerers, I am willing to admit that my mind
is so shallow that to me our ordinary vision and other
perceptions, are quite as wonderful as any of the
alleged wonders of clairvoyance, and, that I believe
we don't wonder at vision, hearing and feeling, only
because we have been familiar with them from child-
hood.
THE HARMONIOUS BLACKSMITH.

WHY I DESIRE TWO RANKS OF MANUAL
KEYS TO MY HARMONIUM.-REPLY TO
**ELEVE."

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Australian animal, to be a beast with a bill. Like Sartorius, the foreigner will, sooner or later, demand payment, and just as I should be compelled to export" some medium of exchange-say sovereigns or bank notes-from my pocket, or the balance at my banker's, and deliver it into the pocket of the ornithorynchus-I mean the tailor-in satisfaction of the claim in his "little bill," so must we, sooner or later, export some kind of wealth to satisfy the foreigner's claim for the balance due to him irom our excess cf imports over exports.

This balance may be paid in a great variety of ways. Thus, it may be a direct remittance of goods of British manufacture, or of coal raised in Britain, to the foreign merchant to whom the balance is due. It may also be in the form of the precious metals not raised in Britain, but purchased with the products of British industry-for, be it remembered, gold and silver are as certainly, and only can be, purchased, by exchanging British manufactures for them, as French, Portuguese, and Spanish wines, American cotton, Chinese tea, or colonial sugar, are so purchased. Direct trade may be easier to comprehend by those who have not studied this subject, but it is not necessarily more profitable than indirect trade, and, whether we buy tea with silver, previously purchased in Mexico with British manufactured produce, or with calicoes in Canton, it makes no essential difference; in both cases they are ultimately paid for by British produce, exchanged for the foreign produce, and I may add, that just as the export of silver is a positive good to Mexico, which has more silver and less cottons and hardware than her population requires, so is the export of silver from England to China a positive good, both to the Chinese and to us. They have tea to spare, which we want; we have got more silver than we require from Mexico. The Chinese fancy they want more silver than they have, so we indulge their argentiferous fancy, and obtain in exchange "the cup which cheers but don't inebriate." Verily we have our reward.

From the above it will be seen, that no so-called

When solid steel guns were first introduced, our quick-burning powder almost invariably burst them unless made very massive at the breach; in fact, the evolution of force was so sudden that the surface of the powder chamber was burst from within; the material was disrupted before the strain could be SIR,-"Eleve" asks why should 8 rows of reeds get communicated to the outer portions of it, and, for two rows of keys, when one row might do the work? Now, however crotehetty I may be-and, like all harcapability of resistance, the outer parts might as well have been absent. "free to It was this "busting up,' as the dened sinners, I glory in mine iniquity-I am Yankees call it, which induced the Prussian artillerists confess" that I don't know why the aforesaid 8 rows to decline trying Krupp's solid steel guns with of reeds should get two ranks if one row can be made English L.G.. powder, for they, being reasonable to do the work; but that it can is just the thing I men, only wanted to expel the shot with sufficient have not yet been shown. I should like to be. velocity, and did not want to burst their guns. That there may be no possible misunderstanding, I They did not see the economy of the British custom of will specify the work I want my harmonium to be making very costly guns and then subjecting them to capable of doing. N.B.-It is, when properly done, strains not required for any practical purpose, so, really work, although usually designated by the term instead of English L.G.R., they used their own pris-playing. The work wanted is to play a melody with matic powder, which sent the shot quite as far without true vocal expression (whether that expression be adverse "balance of trade" can continue long to affect "busting" the gun. So long as the required range is obtained by the usual means or à la main, which I obtained, what more do you want? Surely, even those greatly prefer), and the accompanying of that melody us injuriously. Silver and gold are, commercially destructive English artillerists ought to be contented by the sounds of other reeds, without the possibility of speaking, mere commodities, and as properly the subthose sounds being swelled to any objectionable extent.jects of trade as the food and clothing of those who I also require that in the performance of the said obtain them by mining. No doubt there are some political considerations involved, to which I, who accompaniment I shall not be limited to F first space, have treated this subject from a purely commercial or any other note within the compass of my harmostandpoint, and assumed the continuance of peace on nium, for the sound of highest pitch with which I may earth and good will to mankind, have not adverted. fancy to accompany the said song or melody. In this I require no more than every organist can do, Perhaps the latter is rather too much to assume vet, for we have not quite arrived at the Millennium. War if he plays his melody on the swell organ, and accomdisturbs commercial exchanges, and when we have to panies it on one of the other organs whose keys are do this on an harmonium with only one manual rank, bank notes or bills on our government, in payment for beneath his fingers. If "Eleve" can show me how to provision an army in the enemy's country, we can hardly expect its native hostile population to accept that matter-of-fact character and remarkable economy in the matter of £ s. d.-however liberal I may be supplies. In this case, of course, only the precious of words-for which he gives me eredit (I only wish I metals will be accepted, and those, unless in the form deserved it) will compel me to admit the second manual of coin current in the country, only as so much rank to be quite superfluous; but until he does this I bullion, for it is obvious that the possession of British can no more work or play without my second rank coin, or its paper representative, would be prima facia of manual keys than I can without that third rank of evidence of treasonable correspondence with the invading army, and war makes short work of treason. keys yclept pedals.

with this!

After a reasonable perhaps I ought to write unreasonable-time had been taken for consideration, our sapient authorities seem to have found out that it is desirable to avoid destroying wantonly our very expensive wrought iron and bronze guns by subjecting them to needless strains, which don't increase the range of the shot, but which do, sooner or later, burst the gun; so at last they have followed the Prussian somewhere about the proper size to burn at the required example of making prismatic powder, whose grains are rate, and having provided the means of ascertaining (approximately) the pressure of the gases in the chase at the intervals of the shots successively passing certain portions of its length, they found the strain on the gun was reduced from 4500 atmospheres when L.G.R. powder was used to 15 atmospheres when prismatic powder was employed. Need I add that by the employment of the latter, not only will the "life" of our guns be prolonged, but that it is very probable the multitude of cast iron guns in store may especially if they be treated a la Palliser-be rendered available for the extremely Christian work of killing the Queen's enemies without much danger to those of her subjects who may have the blessed privilege of doing that work of necessity, if not of nerey, when the occasion warrants that work to be done. May that occasion be far distant, or rather, Heaven forfend its occurrence!

THE HARMONIOUS BLACKSMITH.

MESMERISM.-REQUEST TO "SIGMA." SIR, I much doubt if among all my fellow correspondents in our journal there is another who writes in a more truly philosophical spirit thau "Sigma," and had I not before been acquainted with the facts which are commonly termed mesmerism, to which he bears testimony in No. 257, I do think his testimony would have compelled my credence, for all his communications exhibit plenty of internal evidence that his mind is not one likely to be deceived into belief on insufficient evidence, and that he would wilfully deceive others I deem quite out of the question. Improbability means little else than unexpectedTo me, the facts he avouches seem no more wonderful than any other facts with which we are

ness.

ignorance when the unexpected transpires, and im

I

war.

From these considerations, it follows that we must have a store of gold and silver, just as we require a store of gunpowder, they, like it, being munitions of best kept ready for warlike service by being coined, Whether these especial metallic munitions are allowed to circulate as a medium of exchange-ie, as money, and become depreciated, is quite another question. As paper, which cannot become depreciated, is a yet more convenient medium of exchange than either gold or silver, and, as I have long ago shown, that the only condition required to prevent that depreciation, is convertibility into anything the holder prefers to his paper money. I think it may be assumed that instead of stamping the image and superscription of the reigning Cæsar, or sovereign, on gold, and then allowing it to be wasted by use and loss, that I am justified in believing it would be more economical to store the gold and circulate the paper. But I refrain from boring my fellow readers with my somewhat peculiar notions on the currency question.

It is a great consolation to me to find "Eleve supports my humane (suggested) treatment of reeds, babies, and paupers, but I fear he is hardly prepared to what our American cousins term "the intire Some reeds, like some babies, squall so animal." horribly, that I fear they must, like the niggers, come of an inferior race, utterly incapable of civilisation. am quite hopeless that either these cantankerous reeds or those yet more cantankerous babies ever can be educated by any amount of scentific "treatment" to utter agreeable sounds. The sooner such "vessels of wrath are improved off the face of the earth the better for us all; and in mercy to our weaker brethren, or rather those brethren whose cars are weak and cannot bear "rank and strident tones," both reeds and babies ought to be smothered intirely, as the "finest pisantry" express it. Were some of the pipes of our old city organs sarved that same, it would be no great loss to the musical world; but perhaps, like certain other utterers of evil, it is best they should go to the Why men should understate the real value of hot place, for then they might be "purified by fire," and their material be converted into virtuous pipes, which exported goods is a mystery, perhaps its solution may, might, if well voiced, utter angelic sounds. But, after in sorae instances, be found in the fact that some all, it is best not to be too sanguine; and blessed is he unenlightened foreign governments levy ad valorem who expecteth nothing, for verily he shall not be dis- duties on the importation of British manufactures. If appointed. these are passed at their declared, instead of their P.S.-Perhaps "Eleve" may say that if the expres-cheaper, but it has been suggested that although this real values, of course they reach the native trader harmonium makers seem very shy of attempting, I

THE HARMONIOUS BLACKSMITH.

our exports and imports, it is to a considerable extent

familiar. Wonder is but the usual expression of sion be à la main, which, by the way, most modern may partly account for the different apparent value of probability seldom means anything more than the could swell the melody and refrain from swelling the compensated for by the common practice of declaring incongruity of the unexpected with our very limited accompaniment-I don't feel quite certaia; "swelling," the value of exports greatly in excess of its real knowledge; strictly speaking, we can hardly be justi- however common as a noun substantive, is a correct amount, which is said to be frequently done by that fied in saying that any alleged new fact is impro- true; but then I am precluded from accompanying English verb; but no matter, I shall be understood- race of 'cute merchants who insure ship and cargo bable, however little we may expect its discovery; in with tones of different quality or timbre, unless I limit fact, this allegation of improbability is only the old the accompaniment to the highest note in the bass halffallacy of making our ignorance a measure of the pro-rank-say F, or wherever the ranks of reeds are bability of what we don't know, and I am sorry to add that from the reproach of doing this I cannot entirely crotchet of expression a la main, such as I obtain in So "Eleve" will see that my favourite acquit "F.R.A.S.," who -on the subject of mesmerism the celestina, terpodian, euphenon, or sostinente only-seems to assume that what he is not convinced of, must be at least improbable, if not absolutely false. pianoforte, will not fulfil my requirement.

See his communication in a recent number.

divided.

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says we are exporting less, and importing more, than formerly, and he asks what kind of prosperity this indicates. I hasten to assure him that he may be "quite easy in his mind," notwithstanding the above is a true statement of declared values, and may be temporarily true of real values. That it cannot continue long is obvious, because however good John Bull's credit may be, the foreigner won't trust him ad libitum, but the great probability is, that the declared value of our imports is above, and that of our exports less than their real values.

Having had but little personal experience of the
COMMERCE AND TRADE.
higher phenomena of clairvoyance, I should, I trust,
in common with many of my fellow readers, who are SIR,-Under the above title-which, by the way, is
earnest seekers of truth, be very glad to be further very much like two names for one thing"Saul Ry-
enlightened concerning those phenomena; may I there-
fore, in their behalf, as well as mine, request" Sigma"
to inform us what instances of the perception of
things and occurrences at distances far beyond visual
ken, and notwithstanding the interposition of opaque
substances, he has witnessed. "Sigma" will of course
understand I allude to such phenomena as the percep-
tion of the fire raging at Stockholm, by Emmanuel
Swedenborg, when he was dining in Berlin; or the
celebrated case of the young girl, whose name I
forget, who accurately described the furniture and
contents of a room many miles distant from her,
which she had never seen by ordinary vision, or
indeed knew the existence of, until placed en rapport.
I greatly fear some of the intellectual descendants
of unbelieving St. Thomas will be tempted to cast
ridicule on me for asking for such information in

at three times their value, in the hope they may never arrive at the port to which it is pretended they are consigned. I am told this little game pays very well when you are not found out, in which case you are "paid off" instead. As Hercules was said to help the industrious who had a habit of helping themselves, so, perhaps, Satan helps-through the instrumentality of the trusted captain or matethose who help themselves to the underwriter's money in this honest way. Verily, I hope they also may have their rewards, a hope that I am confident" Sigma," and every other honest mariner, who has a reasonable prejudice against drowning half the crew to enrich scoundrels, must share.

It is

THE HARMONIOUS BLACKSMITH. P.S-Since the above was written, I see "Sigma" has taken this subject in hand, on page 184. said that if you mention a certain much maligned person's name, he straightway appears; and in this respect "Sigma" emulates him in playing the dwith the popular fallacy of the balance of trade, but may I ask him if-in a scientific sense of the wordany profit, other than mutual benefit, ever can result from trade, foreign or domestic? I trow not; if by If our imports are of greater intrinsic value than profit we mean getting the greater value for the less. our exports, it is obvious we must be running into When I exchange half-a-crown for a pound of tes debt, and we shall have to export more to balance the seller gets no profit in that sense, for he has the account. The foreigner will no more trust John given me half-a-crown's worth of tea for two shilBull without limit, than that first cousin of the orni-lings and sixpence; truly, it did not cost him so thorynchus, our tailor,-Punch defined him, like the much in money, and the difference is commonly

called his profit; but it might be more truly termed his wages, or remuneration for selecting, preparing, and supplying the tea. Perhaps, also, some part of the difference between its cost and selling price is payment for gratifying our aesthetic taste by the extremely artistic decoration of his shop. Surely. when much gold leaf and artificial mahogany are exhibited for our gratificaoion, we ought, like the frequenters of that temple of delight, the gin palace, to contribute our proportion of the cost of those decorations which we enjoy. This is no more than justice to their puryeyor; but perhaps the great profitableness of co-operative stores, in which such decorations are as rare as stained windows and pictures in a Dissenting chapel, might go far to teach us that such gorgeous decoration is not absolutely essential fer retail trade, and that people of more quiet tastes, may even manage to get their tea, &c., without them. But whatever the concurrent conditions, the fact remains, that we somehow get the same value in another form that we part with in coin. As the authorities on political economy express this fact, "all honest cominercial transactions are exchanges of things of equal value" in the aggregate. So I trust "Sigma" will see, that although our foreign trade yields no profit, in the sense of our imports being of greater total value than our exports. that fact does not necessarily cause us to be in what he terms "a bad way."

As it is said the absence of condemnation is = approval, so "Sigma" is quite welcome to assume that all the rest of what he says on this subject will pass muster; in fact, his conclusions regarding the accumulation of wealth by Britons, and their proclivity to waste it in foreign loans, when the most promising works at home are languishing for want of capital, now lying idle, which might be profitably invested in them, are quite indisputable, but he will allow me to remark, that this is rather the result of our experience of trade morality (Query, immorality) than any prejudice the British capitalist has against investing his money in home works. We have not yet forgotten Black Friday in 1866.

INDUCTION COIL.

SIR,-I am building an induction coil, of which the reel is 9in. long, with gutta percha ends fin, thick, 44in. diameter. Arguing, in my own mind, that the spark may escape as easily in a lateral direction from one convolution to the next, as from one layer to another, I have begun laying the secondary wire with a strand of cotton thread interposed between them, and this se parating of the coils I intend to increase as I inerease the insulation between the layers. I calculate on thirty layers, and the first ten are insulated thus: First well coated with shellac, next a piece of the soundest brown paper procurable, is cut the exact size, that is softened in water, glued, and wrapped round as carefully as possible, and when quite dry, thickly varnished. The second ten will have two thicknesses of paper, and the third three. The primary is two layers, No. 16, and the core an inch and an eighth diameter. I find the work one demanding, above all things, patience, as, taking stoppages into account, three layers a week are as much as one can manage. The opinion of fellow workers in the mechanics of science, will oblige.

M. G. CUNNINGHAM.

STRENGTH OF CHAINS.

SIR,-As my only desire was to correct an error in rule, not to point out so small a discrepancy as 001, nor yet cause Mr. Tolhausen to work to 4 places of decimals; took in hand the examples as given by him page 123, and gave my reason (why and wherefore) 32 should be used as a divisor or multiple in working out correctly the examples, page 163. As Mr. T. invites me, page 186, further to use my skill in working out a more precise rule, I prefer choosing, as an example of rule given by me, a 24in. chain, and show the result in figures without remainder, so that it may be easily understood: = 50 tons.

Rule by eighths (as given)

Rule by sixteenths (as given)

202

8 402 -= 53 tons. 30

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SIR,-I cheerfully respond to "Maschil's" request, and I shall be pleased to give him any further information he may require on the subject. I am afraid our courteous friend, " F.R. A.S.," has entirely overlooked the request of "Saul Rymea" and myself respecting the tide tables. I enclose an excerpt from the Thanet Guardian for April 2, which indicates the time of high water at Margate to be exactly two hours earlier than at London Bridge. When doctors disagree, who is to decide ?

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expressed in sidereal time, admits of a fuller development than has been made on pp. 70, 86, 135, and 159. See letters of "F.R.A.S." and "Not an F.R.A.S." Thus-1800 12 hours of longitude, whether the instrument used for measuring it be a theodolite, a mean time, or a sidereal time clock. because the iden of duration is excluded. It is angular magnitude, and the velocity of the clock's hand in revolving through the angle, does not affect the equation. In illustration of this, I append the example of page 86, wrought out as nearly correct as I can do it, to 4 decimal places of a second, by three different methods.

1st Longitude, considered as Mean Time.
k. m. 8.
1 33 46-0710
1-3333

Greenwich sidereal time at noon.
Correction for 8m.7s.of longitude.
Local sidereal time at noon.
given sidereal time.

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1 33 6 14

47-4043

2270

50 3900 =

2077

Yolk of egg

2051

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Grape sugar

2033

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Hard-boiled egg

1415

40

53-2831

1-9945

Mean time equivalents.

Bread crumb

1333

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FUNCTIONS OF FOOD. SIR,-Your remarks on "The Value of Different Articles of Food " (p. 107), are replete with interest to those that have devoted any attention to the subject. The fallacy of Liebig's classification of the functions of food has of late been shown by the most conclusive experiments of many chemists and physiologists. Their researches have entirely broken down the distinction between the so-called "flesh formers" and "heat givers" by proving that the former, or nitrogenous, principles are also capable of developing a certain amount of muscular force and heat in the system. Hence they are now appropriately termed, "flesh and force producers." On the other hand, the

hydrocarbons or "heat givers" generate heat and muscular or mechanical force, and are consequently now called "force producers."

Sometime since Professor Frankland, who has devoted much attention to this matter, published the results of a series of investigations made for the purpose of ascertaining the maximum amount of power or force which it was possible to obtain from a given quantity of different foods. A notice of these investigations would, I think, be a valuable sequel to your excellent article. In introducing the subject the learned Professor observes :

Both the heat force and the mechanical force generated in the bodies of animals are derived from food. An animal, however high its organisation may be, can no more generate an amount of force capable of moving a grain of sand, than a stone can fall upwards, or a locomotive drive a train without fuel. All that such animal can do is to liberate that store of force which is locked up in its food. It is the chemical change which food suffers in the body of an animal that liberates the previously pent-up forces of that food, which then make their appearance in the form of heat and mechanical motion.

All the combustible ingredients of food, whether nitrogenous or not, are capable of yielding mechauical force and heat force; but the nitrogenous constituents, such as albumen, fibrin, and casein, can also be used in the body for the building up of muscle or flesh, hence these constituents are termed flesh and force producers. The non-nitrogenous ingredients of food, such as starch, sugar, and fat are incapable of forming flesh; they are force producers only. It is the oxidation of the non-nitrogenous matters in the body which constitutes the chief source of muscular power. The muscular force expended within the body takes the form of heat, and is the chief if not the only source of animal heat.

ham, boiled.. Mackerel.. Whiting White of egg Hard-boiled egg Isinglass Milk Carrots Cabbage Cocoo-nibs Butter Beef fat Cod-liver oil Lump sugar Commercial grape sugar

Bass's pale ale (bottled).. 9 bottles 10d. per bottle. Guinness's stout 61

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* It is not to be understood from this that taking 1lb. of cod liver oil would enable a man to lift onefifth of 5649 tons (that is, 1130 tons) one foot off the ground. What is meant is, that that is the total mechanical work which the combustion in the body of 1lb. of the oil is capable of producing outside the body, supposing its effect to be wholly expended in the production of this mechanical work without any waste. Moreover, this statement of the amount of work in tons lifted one foot does not take time at all into account. It simply reckons the total work which it is possible to get out of the combustion of 11b. e cod-liver oil, no matter how long it may take to e

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