we may assume for P what we please. The last factor, therefore, is the only variable one, and its variation depends solely on that of the angle CBD, or ABA', the other angle, BDC, being a function of this, and of the sides, BC, CD, which are given, and equal to 11 and 3 respectively. If, therefore, we wish to know the actual power of this press, and also the increase of power consequent upon a diminution of the angle ABA or CBD, we shall have to substitute in the above expression the values of BA

P and for these quantities, and likeBC

wise to give successive values to CBD. The results will be the values of W, or the power exerted by the press, for each particular value of the angle CBD; and the differences of these results will be the increase corresponding to each diminution of that angle respectively. However, as W varies, for the same value of CBD, directly as P, it is evident, that if we call P1 pound, we shall be able, simply by multiplying the value of W, obtained on that supposition by any number assumed for P, to find the value of W corresponding to that value of P. Cailing P 1

103 03 164 2 &c.

We here see that while, when CBD is 25o, a diminution of 5° occasions an in.. crease in the value of W of 22.8 per cent.; a diminution of only 20, when CBD is 5o, occasions an increase in that value of no less than 1642 per cent Also, if we desire to know the absolute power of the press when P is, say 20 pounds, and the angle C B D, 3o, we find 226 18 x 204523'6 pounds.

There are, as has been already stated, certain deductions to be made from the results in the second column, on account of friction and the imperfect rigidity of materials; and these deductions increase as we diminish the angie CBD. Since, however, they may be indefinitely reduced by careful construction, it is unnecessary to calculate them, if indeed that were possible.

I have said that the performance of this press answers my expectations; I send you some specimens, that you may judge for yourself.

I am, Sir,

held on Monday last, Earl de Grey, the president, in the chair

σε

Mr. Papworth, V. P., read a paper on the benefits resulting to the manufactures of the country from a welldirected cultivation of architecture and the art of ornamental design, as an essential portion of its study."

Mr. John Britton offered some observations upon the style of Domestic Architecture prevalent in England from the time of Edward IV. to that of James I., illustrated by numerous drawings of old mansions of that period.

A Memoir was next read on the value to Architecture of the Stone-planing Machine, lately invented and patented by Mr. James Hunter, of Leysmill, Arbroath (noticed in Mech. Mag., present vol. p. 73.). From this me appears that the distinguishing features of Mr. Hunter's invention are,

1st. That the rough surfaces of blocks of stone are subjected in an intermitting succession to the operation of the planing machine; the blocks being removed as they are finished at one end of the machine, while new blocks are supplied to it at the other.

2d. That the planing tools can be readily adjusted to any thickness of surface, which may be required to be cut away.

3d. That the greater the thickness of surface, which the tools are employed to cut away, the greater is their efficiency, and the less they are injured.

Aud, 4th. That the tools are so firmly yet temporarily secured in their places, as to perform their office without any ́appreciable_shaking or recoil, while, at the same time, they can be easily removed as they are worn, either for the purpose of repair, or of being replaced by new tools.

The principle on which the third of these advantages, the greatest and most startling of the whole, is obtained, was explained in this way. When the stones are placed ready for planing, the roughing tools, as the two which come first into action are called, are so adjusted that they shall strike each block as it passes under them, at such a depth below the top surface, as to sever and throw off before them large portions of the stone at a time, taking care always that the

depth shall be within such limits as that the line of least resistance shall terminate in the top surface of the stone, so that the fractures shall all tend in that direction. Hence, the greater the thickness of stone cut away, the greater is the advantage, inasmuch as the lengths of stone severed and thrown off at each shake, are always proportional to the depth of the cutting, and, in like manner, the rest allowed to the tools, and their consequent exemption from beating and abrasion, is proportional to the lengths of stone separated from the surface at each stroke. For example, the wear of iron is less by, perhaps, one-half in taking off an inch at a time than in taking off half an inch; and to take off an inch of stone in two operations, will go far to quadruple the loss of iron.

The number of tools employed is only four-the two roughing ones just mentioned, which are round and pointed, and two finishing ones with broad mouths. In a late patented (but we believe abortive) machine of this description, the number of tools amounted to nearly forty. When a stone has passed under the roughing tools, the surface is commonly left in ridges, and these ridges it is the business of the finishing tools to clear away. The fac ing given to the stones by the new operations is so smooth, and, at the same time, so sound, that they can be afterwards polished for one-half of what it costs to polish stone prepared for the purpose by hand.

From calculations given in the Memoir, it appears that the cost of planing a superficial foot of Arbroath stone costs only four-tenths of a penny; while to do the same work by hand, would, on the very lowest estimate, cost four times

as much.

The Arbroath stone is particularly fitted for street-pavement and stoneflooring. It resists damp much better, and dries more quickly than the Yorkshire flag. Slabs of it dressed of an equal thickness, and polished on both sides, can now be supplied in London for about ninepence per foot. In Scotland this sort of stone is now getting into extensive use as a substitute for marble; when painted in imitation of scagliola and well varnished, it is pre

ferable to scagliola, and not half so expensive.

Mr. Hunter's machine, when coupled with a lathe, is capable of turning as well as planing stones. A very satisfactory proof of this was exhibited on the table of the Institute. It was a handsome vase presented to the Institute by Mr. Carnegie, the proprietor of the Leysmill quarries, 20 inches high and 18 across the mouth, which was turned out of the solid block by Mr. Hunter in the course of a single day's work; and is, in point of accuracy of outline and beauty of finish, worthy of all admiration.

Mr. Carnegie, who was present, said that he had no doubt that all stone of no greater hardness than the Arbroath, can by means of this machine be turned as fast, and nearly as economically, as wood. He would undertake that Mr. Hunter should diminish the diameter of a large grindstone a whole inch at one revolution, without materially injuring the tool employed.

GRAY'S RAILWAY SYSTEM. Sir,-As the original proposer of the railway scheme, allow me to recal to the serious attention of your readers, the glaring error committed by the Liverpool and Manchester Railway Company, in the construction of their railway; which was pointed out by me in a circular published on the 1st of May, 1830 (see your Magazine of that tiine.)

Can there be any wonder at the indifference of the public with respect to railways, when we witness the wanton mismanagement of the railways hitherto established?

Every national benefit is sacrificed to private views, or to particular interests.

The speed with which passengers are conveyed is always blazoned forth, and kept up at a ruinous expense, merely to cover the ignorance of the engineers, who contrives to blind the public to the real advantages of railways worked by the double system of cog and plain rails -cog rails, for the exclusive conveyance of merchandise of every description, and plain rails for the express purpose of conveying passengers, mails, and light vehicles of every denomination.

Until these two systems become united, and adopted by the public, in the establishment of Grand Trunk Rail

ways, in direct lines and on perfect levels, from London to each extremity of Great Britain, and from Dublin to each extremity of Ireland, as laid down in my numerous petitions to Government on this most important subject, depend upon it, sir, all present attempts at the formation of railways must ultimately terminate in disgrace to the engineers. All that has hitherto been done in railways, must be done over again ere the proprietors can find a sure and permanent revenue.

The Liverpool and Manchester Railway, notwithstanding the dividends, is a decided failure, which might be proved at any time. Truth and experience will break the seals of secrecy, and the bubble must then burst! Had this railway been constructed agreeably to my suggestion, the canal in that district would not have carried a ton of merchandise a week.

In one of my former letters I asked you, sir, if the proprietors of the Duke of Bridgewater's Canal had no interest in the railway? Give the railway fair play, and I am sure the rates of carriage and of fares might be reduced one-half.*

66

In some of the recent Numbers of your Magazine, I observe a series of letters signed John Herapath." Pray, sir, is this the same gentleman who inemorialised the Duke of Wellington in favour of Gurney's steam-carriage pranks on the turnpike-road, some years ago? By-the-bye, Gurney's in the field again!! so the papers tell us-but where's the game? A steam-carriage is the baitbut where are the gudgeons?

At the very time Mr. Herapath was addressing his Grace, I had also taken the same liberty; and herewith I transmit you, in part, a copy:

"Every attempt to run steam-carriages on the common turnpike-road must, and ever will, prove both ineffectual and profitless; whilst the same engine would always, under all circumstances, propel ten times the load more, and at a much greater speed, on rail ways!!"

I perfectly agree with Mr. Herapath, that tunnelling is unnecessary; it is, however, a mania which, unfortunately for the purses of the deluded subacribers, has seized upon our civil en

This railway might certainly have been better constructed, and may, perhaps, be under some sinister influences, but to describe it as a "decided failure" is surely a decided mistake.-ED. M. M.

gineers, who seem to be delighted in doing every thing to blast the success of railways. I really am much astonished that Government should so long refuse to listen to my petitions for the establishment of a National Railway Board in London, to superintend the construction of railways throughout Great Britain and Ireland, under one specific plan, without which every railway may vary according to the whim or fancy of different engineers.-Yours, &c.

THOMAS GRAY, Author of "Observations on a General Iron Railway."

NOTES AND NOTICES.

The gentleman of whom we spoke in our remarks on Lord Brougham's Patent Law Amendment Bill, as having been "Solicitor to the abortive Bill of 1833," and as having no call, save his share in that abortion," to be one of the select triad who gave evidence before the Select Committee of the Lords, has written a letter to the Times journal, which did us the honour to copy our remarks, in which he says-"If the writer in the Mechanics' Magazine had furnished you with a copy of the Bill to add in the Times, as he could not avoid doing in the Magazine, to his observations, I think they would certainly prove as harmless, as in truth they ought to be." If it is meant by this to charge us with sending a copy of our remarks to the Times, and keeping back the Bill to which they refer ed. from an apprehension of its destroying the effect of these remarks--the language, indeed, admits of no other meaning-the writer has then a very gross misrepresent tion to be ashamed of. Reason to suspect us of such disingenuous and unfair conduct, there was none, but on the contrary, good reason to be convinced that the reverse must have been the case. The same number of the Magazine which con'ained the remarks contained also a copy of the Bill. That the Times zave the one without the other, is no fault of ours; nor much fault in the Times either, if we may judge from the request with which the gentleman concludes his letter. One would have thought that it would have been a request to publish the Bill which he affects to regard as a complete answer to our remarks, but no - it is a request to publish "my Evidence"!!! The Times having declined publishing dence," it has been since sent to ourselves with a request that it may be published in our pages. As we have no desire, however, to have our Magazine regarded as an asylum for rejected articles, we, too, must decline.

"

my Evi

H.-We are not aware of any thing more re

cent.

Thomas Walker, of Burslem, mechanic, for improvements in extinguishers to candles, and in the application of such extinguishers to candles and candlesticks. July 3; two months to specify.

Janies Kean, of Johnston, county of Renfrew, machine-maker and engineer, for an improved throstle-flyer, or a substitute for an ordinary flye, employed in spinning cotton, flax, hemp, wool, silk, and other fibrous substances. July 3; six months to specify.

Henry Vint, of Louden, in the borough of Col. chester, Esq., for certain improvements in paddlewheels. July 9; six months to specify.

Richard Coad, of Liverpool, manufacturing chemist, for certain improvements in the means or, apparatus for consuming smoke and economising fuel in furnaces, which improvements are particu larly applicable to the furnaces of steam-engines employed for navigation and other purposes. July 10 six months to specify.

William Busk, of Barkside, Surrey, engineer, for certain improvements propelling boats, ships, or other floating bodies. July 10; six months to specify.

John Rogers, of Pinces-court, Westminster, gentleman, for certain improvements in paddlewheels. July 10; six months to specify.

Conrad George Kuppler, of Nuremburg, at the Polytechnical Institution, but now of Birmingham, for certain improvements in the construction of weighing machines, and other machines used in ascertaining weight. July 11 two months to spe

cify.

Frederick Herbert Maberly, of Bourn, county of Cambridge, clerk, for a new method of propelling vessels. July 13; six months to specify.

Joseph Chesseborough Dyer, of Manchester, machine-maker, and James Smith, of Dunstone, county of Perth, cotton-spinner, for certain im provements in machinery used for winding upon spools, bobbins, o barrels, slivers or tovings of cotton, wool, and other fibrous substances of the like nature. July 17; six months to specify.

William Vichers, of Sheffield, merchant, for im proveme in machinery, for preparing or shaping steel for man facture of files and rasps. July 17; two nhs to specify.

Joseph Henri Jerome Poittevin, of Craven-street, county of Middlesex, gentleman, for a powder which is applicable to the purposes of disinfecting night soil and certain other matters, and facilitating the producting of manure, being a communication from a foreigner residing abroad. July 17; six months to specify.

John Dickinson, of Bedford-row, Holborn, and William Long Tyers, of Apsley Mill, in the parish fing's Langley, in the county of Hertford, for certain improvements in the manufacture of paper. July 24; six months to specify.

Thomas Horne, of Aston, near Birmingham, brass-founder, for certain improvements in the manufacture of hinges. July 24; six months to specify.

Patents taken out with economy and despatch; Specifications prepared or revised; Caveats entered; and generally every Branch of Patent Business promptly transacted. Drawings of Machinery also executed by skilful assistants, on the shortest notice.

Our Publisher will give One Shilling and Sixpence for copies of the Supplement to Vol. IX.

LONDON: Published by J. CUNNINGHAM, at the Mechanics Magazine Office, No. 6, Peterbo rough-court, between 135 and 136, Fleet-street. Agent for the American Edition, Mr. O. Rick, 12, Red Lion-square. Sold by C. G. BENNIS, 55, Rue Neuve, Saint Augustin, Paris. CUNNINGHAM and SALMON, Printers, Fleet-street.