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It has heretofore been deemed impracticable to grind and dress simultaneously; but we have been informed, that all the millers who have seen Mr. Hebert's machine have entirely changed their opinions in this respect, the flour produced by it being unexceptionably good; and it is perhaps worthy of remark, that owing to the grinders being entirely metallic, there is no possibility of having gritty flour from them, which is sometimes excessively unpleasant in bread made from flour produced by the ordinary mill-stones. appears, however, from the specification of the patent, that the invention does not consist in the material of which the machine is formed, but lies in the mechanical arrangements, which are defined to be these, if we recollect rightly :-The grinding and dressing of wheat, or the reduction and separation of other substances, by means of a single machine, in which the grinding and dressing operations are conducted upon one continuous surface; or wherein the meal, as it is projected from the circumference of the grinders, is received into a sieve whereon it is dressed. The patentee seems to give the preference to metallic surfaces on the ground of his having made great improvements therein, especially as relates to the easy means afforded of giving the grinding surface an unusual degree of truth; and that kind of roughness which so nearly approximates to the French burrstone, as he expects will lead to the entire abandonment of the latter. An example of the application of burr-stones to these patent "flour-makers" is, however, given in the specification, as the invention equally embraces them.

It has long been anxiously desired by philanthropic legislators, that a substitute might be found for the horrid and degrading punishment of the lash. Now, we are strongly impressed with the idea, that a machine of this kind, but of the size described in our previous Number (665), is admirably adapted to effect the object in view, as the offender might thereby be easily made to atone in confinement for his offence, by grinding á given quantity of corn, as the condition

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of his liberation-say, for instance, a bushel for getting drunk, a sack for insubordination, and so forth.

ON AEROSTATION.

Mr. Editor, If the following remarks possess sufficient merit to entitle them to a place in your popular Magazine, a weekly peruser of it will feel happy at seeing them inserted in one of your forthcoming Numbers, in the hope of their drawing to this wonderful art the attention of some more opulent, learned, and scientific person than

Yours, &c.

OMRI.

Upwards of half a century has elapsed since the introduction of aerostation; essays on which have from time to time appeared in the Mechanics' Magazine; but although I differ in opinion with most of the writers of those essays, particularly the bird-fancier, I shall not here make any remarks upon their lucubrations, controversy not being my object, but a desire to ascertain the causeWhy, when almost all other arts and sciences are progressing towards perfection, the art of flying remains stationary? Every succeeding attempt is limited to merely ascending and descending where and how the adventurer best can, not where he would; all his other movements being "the sport of winds-scorning the guidance of man." Is there any sufficient reason why the art of voyaging in an element far less dense than water, should not be performed with the same precision, safety, and rapidity, as on land or water?

A paragraph lately went the round of the papers, and appeared in your Number of April 16, stating, that Dr. Amge had read an essay at the French Institute, endeavouring to prove that balloons might be guided by means of oars inflated with gas used in the car; but as I consider this to be merely a renewal of Montgolfier's attempt, with very little amendment, I shall only here remark that, if understand the learned professor rightly, such a contrivance cannot answer the purpose; that is, if he means after the manner of a boat towing a ship, because a boat to tow a vessel or raft must be placed on a line in advance of the object to be towed. Now to effect this, either the car must be elevated from

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LOCOMOTIVE-ENGINE EXPERIMENTS.

its present position, or the balloon must descend to a level with the car; but how either could be retained in such a position, I am at a loss to conjecture; I should as soon expect to see a ship steered by the rudder of a boat that was towing at her stern, as to witness a balloon, driven, perhaps, by a strong current of air, guided by any puny effort that could be made in the car.

I come now to inquire into the failure of the practical aeronauts of the present day (one of whom is said to have made upwards of two hundred ascents), who, with improved materials of every description, appear to have profited nothing by experience-balloons being now as nearly similar as two things can be to what they were when first invented. Mr. Green, who manufactures his own cloth, has, indeed, announced his intention of making a balloon of sufficient capacity to carry up ten persons. This enlargement appears to me to be neither more nor less than an expensive perseverance in misconstruction; for, viewing it in a homely light, who would feel disposed to extol the abilities of a housewife com. petent to make a pudding for two persons, because, on being furnished with a sufficiency of materials, she made one capable of satisfying ten? Nevertheless, no one can deny but that courage, perseverance, and expense, have been displayed in the cause. All that has been wanting to the complete success (probably) of the art of flying, is a little of the same inventive or creative faculty to which we owe the steam-engine, the power-loom, and a hundred other valuable improvements.

After a repetition of descriptions, such as we have been favoured with by aerial voyagers for the last fifty years, viz. a view from the clouds of the striking beauties of boats, bridges, and buildings; canals, churches, and crowds; docks, ditches, and drains; ruts, rivers, and roads; vessels, verdure, and valleys, such views as any person may parallel when he pleases, by ascending St. Paul's or the Colosseum, we come to the important announcement, that Mr. Graham is about taking out a patent for a navigable balloon. I have considered this for the last twenty years to be decidedly practicable, and, therefore, shall not, without seeing Mr. G.'s specification, or what would be still more gratifying, the bal

loon itself, attempt to dispute or deny the efficiency of his plan for the end proposed; but, in the absence of ocular demonstration, I have no hesitation in pronouncing it an impossibility, unless the present globular shape of the machine be altered.

Balloons, as the name imports, were at the first made globular, that shape being considered as best suited for containing the vast quantity of gas supposed to be necessary for raising the required weight. As soon, however, as it was ascertained that 2,500 cubic feet of gas were sufficient to raise a weight of 125 lbs. that quantity, and as much more as was barely necessary to raise the balloon and its appendages, should have been compressed into a different shape; but this has never yet been attempted. The same uninanageable shape has only been enlarged to gratify curiosity or conceit, and a desire to obtain the repayment of expenses, has hitherto blasted the hopes of science. To point out more clearly the folly of attempting to make a circular machine manageable, let us suppose the body and wheels of a coach placed on and around a circular carriage, would it not be difficult to procure a driver sufficiently skilled to know what part of the carriage to harness his horses to, so as to give it a progressive motion, without dragging it bodily against all the rules of art? Or if a globular ship had been built, and the management of her entrusted to Drake or to Cooke, would they not have found her more inclined to turn upon her own axis than to any given point of destination?

Should the foregoing remarks meet insertion, I may be tempted to trespass again upon your pages with a few more remarks upon this interesting subject while the mania for it lasts, which now appears to rage in London.

London, August 1, 1836.

OMRI.

LOCOMOTIVE-ENGINE EXPERIMENTS.

Dear Sir,-Should you agree with me that the following fact will be useful information to your readers, you will oblige me by giving it an early insertion in your valuable publication.

Some time ago, while experimenting on a small locomotive model, I found that the application of power in the

LOCOMOTIVE-ENGINE EXPERIMENTS.

double-stroked locomotive steam-engine, with cylinders laid horizontally, is, contrary to the opinion of most engineers, very different in every other stroke; that is, when the piston is propelled forward, in the direction in which the carriage is moving, the force of the steam is communicated to the wheel by the pistonrod, and, of course, produces angular motion. But on the next stroke, or return of the same piston, the cylinder itself, by the pressure of the steam on the end flange towards the front of the carriage, propels the carriage in a right line forward, and leaves the piston behind the whole length of such stroke; but as the piston-rod is connected to the crank of the axle of the wheel, it (the piston) is brought home to its situation again by the wheel every other stroke.

These considerations will fully show, that the application of the power of our present double-stroked locomotive-engines is not, at the present day, understood. For it is evident, that the force of steam is differently applied each succeeding stroke of the engine: one stroke of the engine applies the force by the piston-rod to the wheel; while, in the other stroke, the force is applied, on the rocket-principle, by the cylinder becoming the propeller, as before stated; and these different applications of force are necessarily productive of very different effects the one producing angular or central, and the other decidedly rectilinear motion. From this discovery it becomes a matter worthy the serious consideration of all railway engineers, to draw a comparison betwixt these two applications of power, in order to prove the difference of their respective effects.

The first law of motion laid down by Sir Isaac Newton, is in the following words:"Every body perseveres in a state of rest or of uniform motion in a right line, unless it be compelled to change that state by forces impressed thereon." This is fully corroborated by

more recent writers.

Dr. Young has the following remark on the subject of angular motion :"When a body is retained in a circular orbit by a force directed to its centre, its velocity is every where equal to that which it would acquire in falling by means of the same force, if uniform through half the radius, that is, through one-fourth the diameter. This proposi

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tion affords a very convenient method of comparing the effects of central forces with those of simple accelerating forces, and deserves to be retained in memory."

My method of coming at this comparison experimentally, was as follows:-I

described a large circle upon a wall sixteen feet high, and fixed a pin in the centre, having drawn two lines across the diameter through the centre, at right angles to each other, I then took two balls (ivory billiard balls) of equal size and weight; to the one ball a silk thread the length of the radius was attached, and the other end of the thread was tied round the pin in the centre of the said circle. One of the balls A was placed at the top of the circle, and the other, B, attached to the thread at the horizontal line level with the centre; and when both were let fall at the same instant of time, they invariably met at the bottom of the circle, striking at C every time the experiment was tried. Now it is evident that the ball A falls with free motion in a straight line, while the ball B, by the string being attached, is confined to move in a circular orbit, and produces angular motion. And when we compare these two applications of force (both acted upon by gravity), it is clearly proved by the foregoing experiment that a body A in free motion in a straight line falls through twice the perpendicular height that the body B does in the same time; the latter being subjected to angular or confined motion, while the former A falls freely in a straight line, and consequently produces rectilinear motion. In order then to com

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SYMINGTON'S PLAN OF CONDENSATION ANTICIPATED BY MR. HOWARD.

pare these two velocities with each other, the velocity of A will be 64 × 16= 32.0000; the velocity of B will be √64 × 8 = 22·6274. These quantities, therefore, as the quantities of matter are equal in both, must represent the quantity of motion or momentum of each, and clearly demonstrates the advantage of applying force in a rectilinear direction over that which is applied circularly.

If, then, the foregoing theory be admitted, and of which I have no doubt, our present locomotive steam-engines should be altered, in order to render this principle of avail at every stroke.

I remain, dear Sir, yours,

PRACTICUS.

MR. SYMINGTON'S PLAN OF CONDENSATION

ANTICIPATED BY MR. HOWARD.

Sir, It is right to state that the plan of condensation communicated by Mr. Symington in your last number, is precisely the same in principle or method as that for which I obtained a patent several years back; being, as stated in my specification, "essentially the withdrawal of the warm water from the vessel or vessels in which the vapour is condensed, and injecting it again amidst the vapour, the heat in the mean time having been abstracted from it."

Whether this is effected by passing the water of injection through a copper worm coiled around the condenser, and lying in a cold water cistern within the frame of the engines, as in my steam-vessel, the Vesta, and shown in the drawings attached to the specification, or by passing a pipe along the ship's bottom, as proposed by Mr. Symington, is quite immaterial. These latter not being new in themselves, are not matters of invention, but of arrangement merely.

I may add, that the process answers completely, and that Mr. Symington himself saw it in operation at the King and Queen iron-works, Rotherhithe, upwards of two years ago. The principal advantage resulting from this form of condensation over that by external cold applied to the steam itself, is the great reduction of the size, weight, and expense of the apparatus. In the former the liquid is slowly cooled by passing along the pipe or other surface, and the steam instantly by the injection. In the latter the steam is, or rather perhaps is

attempted to be, instantly cooled on the
surface, which must therefore be very
extensive. The water of injection may
be cooled at leisure as it were, and with
a moderate surface; but the steam, in
order to obtain a due effect on the ma-
chinery, must be cooled instanter.
I am, Sir,

Your most obedient Servant,
THOMAS HOWARD.

London, July 30, 1836.

THE PATENT LAWS.

Sir,-As there is likely to be ere long some alteration in the law relating to patents, it will perhaps not be thought out of place if I should, through the medium of your valuable journal, make known an idea that has occurred to me on that subject for the greater protection of patents taken out for small machines, such as pencil-cases, pens, &c. If the patentee of the improved pencil-case were to attempt to punish all those persons who have encroached upon his right of patent, it would occupy him years, and then he would not be safe, for others would immediately commence making them again; and this, in my humble opinion, will always be the case while such unprincipled men find customers ready to purchase them. Now, the simple plan I have to propose for the consideration of the framers of the new patent law is this:-That every patent machine shall have the patentee's name in full, and also the date on which the patent was taken out, written on some conspicuous place; this being done, a heavy penalty should be inflicted upon all persons purchasing, or having in their possession, patent machines without the above mark.

*

Trusting you will not deem the above
remarks unworthy your attention,
I beg to remain,
Your obedient servant,
DAVID SMITH,

Leamington, Eagle Foundry,
June 8, 1836.

* When the machine does not admit of the name of the patentee and date of patent being attached to it, the penalty should extend to all persons selling or offering for sale the same without the authority of the patentee, which written authority should be placed in a conspicuous place in the shop where patent articles are sold.

BRITISH MUSEUM.

MAGNETO-ELECTRIC APPARATUS.

Sir,-As it is my intention to construct a magneto-electric apparatus similar to the one represented and shortly described by Mr. Rutter, in No. 560 of the Mechanics' Magazine, I should feel particularly obliged to that gentleman (or any other of your correspondents who possesses such an apparatus,) if he will describe more fully the various parts belonging to it. I should not thus intrude, but that it appears to me to be an apparatus requiring_considerable nicety of adjustment; as I know a gentleman who has constructed one, in which the compound magnet is very powerful, but which is, nevertheless, quite inactive: I infer from this that the size of the armature, and the length and size of the copper wire forming the helices, are of considerable importance. He will confer an additional favour if he will inform me how the decomposition of water is effected by this apparatus.

I remain, Sir, yours, &c.
G. S.

Birmingham, May 22, 1836.

BRITISH MUSEUM.

The following petition was presented to the House of Commons on the 2nd inst. by the Chancellor of the Exchequer, and we trust it will be the means of securing to the world of literature and science that access to the treasures contained in the British Museum which a good classed catalogue alone can afford, for it would be futile to institute a comparison between this and a mere alphabet of names. To the Honourable the Commons of the

United Kingdom of Great Britain and Ireland in Parliament assembled. The humble petition of John Millard, of Arlington-street, Camden Town, Lon

don, Showeth,

That by certain returns presented to your honourable House in the year 1833, it appears that there were in the year 1832, 218,957 printed books, 21,604 volumes of manuscripts, and 19,093 charters in the British Museum.

That several petitions have been presented to your honourable House during the present session, signed by many distinguished scholars and scientific persons, praying your honourable House that a

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classed catalogue of these treasures might be printed and published in a convenient form and at a reasonable rate.

That, in the opinion of your petitioner, such a work would be a boon conferred on the world of literature, is indispensable to all who are engaged in literary or scientific pursuits, and is infinitely superior in point of utility to any alphabetical catalogue that could be formed of the books and manuscripts.

That Mr. John Murray, of Albemarlestreet, at the suggestion of your petitioner, has offered to print and publish, at his own risk, classed catalogues of the books and manuscripts in the Museum, if printed in octavo and sold in parts, and that by this means many thousands would be saved to the public.

That your petitioner has witnessed with the deepest regret, that in the report of the Committee appointed by your honourable House to inquire into the condition, management, and affairs of the British Museum, printed among the votes of your honourable House of the 14th inst., there is no recommendation to your ho nourable House on the subject of classed catalogues, nor any notice of Mr. Murray's offer.

That your petitioner has reason to believe that an alphabetical catalogue of the printed books is now in course of preparation, and that it is the intention of the Trustees of the Museum to print this catalogue at the national expense, probably amounting to some thousands of pounds, to the exclusion of a classed catalogue, which might be printed and published without any demand on the public purse.

Your petitioner, therefore, humbly entreats your honourable House, that your honourable House will be pleased to direct the Trustees of the British Museum, 1. Not to print the alphabetical catalogue of the printed books now in course of preparation, which in your petitioner's opinion would not pay a tithe of its expenses, which no bookseller would undertake the risk of publishing, and which would be comparatively useless to the public. 2. To resume and complete the classed catalogue of the printed books, the preparation of which it appears, from the annual accounts of the Museum, has already cost the nation more than 5000l., and to enter

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