the iron-stone and coal being invariably found in the same spot, and thus affording a ineans of manufacturing iron at a cheap rate; the talent and ingenuity of the workmen; the immense spare capital we have in this country; the circumstance of our canals and rail-roads already established, enabling us to bring the raw material from the interior of the country at a very low rate; it would of course take a considerable time before France or any other country could possess any of these advantages, even those which cannot be considered as peculiar only to us, such as canals and rail-roads.

At the three principal places of manufac ture of iron in the neighbourhood of Paris, " do you know what number of Englishmen are employed at each?-I think there are at least from three to five hundred in each of the two principal manufactories, namely, those of Chaillot and Charenton.

Mr. GALLOWAY examined

Is the larger proportion of that_machinery that is forbidden, of the finer or coarser kind?-I consider that both classes are prohibited under the Act; indeed, under the 26th Geo. III. there are very few things in the shape of machinery or tools, that can be permitted to be exported; and those articles of machinery that have been exported are, generally speaking, those articles that the Custom-house officers could not comprehend: a screw, for example, I cannot, by any species of disguise, prevent meeting the common understanding of every Custom-house officer; but a na chine which can generate any number of screws, he has not the least knowledge of, and consequently permits it to pass.

Of your own knowledge, have a great many prohibited articles been exported? -Morally, as well as legally speaking, I believe to a considerable extent.

Are you aware of any instance in which any of those machines have been con verted to other purposes?-I know that machines have been made to appear for one purpose when they were meant for another, and have been converted accord. ingly.

Cannot specifications or descriptions of every new machine, with drawings and models, be easily obtained in this country by any foreigner?-With the greatest facility; for instance, with all our patents, there are regular drawings obliged to be made, and any man who will go to the expense of paying for them will get them. (To be continued.}

WIGHTMAN'S PERCUSSION LOCK. Malton, Feb. 8, 1824. GENTLEMEN ;-In the 18th Number of the Mechanic's Magazine, I saw a description of a percussion lock which I made two years ago. Had I been acquainted with the intention of my unknown friend, the "Admirer of Field Sports," of inserting it in your widely-circulated Journal, I would have given you my latest improvements, which can now only be done

by a new plate; and were I to request this, I could only consider it as an encroachment on your spirited exertions to diffuse useful information by de scriptive engravings.

The best preparation for the prin ing powder for percussion guns is antimony 3 parts, chlorate of potash 1 part. On account of the corrosive properties of the chlorate of potash, it is advisable to use the smallest possible quantity that will be certain of ignition; the above ingredients, if well compounded, form a percussion powder that will fire with the greatest certainty, as has been not only proved by my own practice during the whole of last shooting season, but by the testimony of sportsmen of the first emi

nence.

One great objection to the stronger preparations for priming is, the great and sudden corrosion produced after firing. So violent is this, that should the interval between firing much exceed an hour, the touch-hole is not unfrequently completely closed by a strong rust.-Yours, &c.

W. E. WIGHTMAN.

POSSIBILITY OF A PERPETUAL
MOTION RE-ASSERTED.

Brill Row, Somer's Town,
Feb. 14, 1824.

GENTLEMEN;-Of Mr. Bevan's abilities I will not presume to doubt; that he is acquainted with the laws of mechanism and of motion, the cause which "draws the stone projected to the ground," is of course; yet, with all his knowledge of cause and effect, the nature of fluid or the weight of matter, I do not think it is well in him to attempt to stop the inquiries of the present or the rising generation, as he seems to be desirous of doing, by his demonstration, entitled "No Perpetual Motion." A mechanic, in the ardour of youth, full of impetuosity, will take every fragile structure formed in his imagination as a piece of durable architecture; but it is not so with one who carefully for years considers, who weighs probability against possibility, before he runs the risk of writing against what are called" established facts," though established facts with those who attempt

to overcome difficulties are but as ,customs to the wise. I will tell "R. B.," that what I asserted, I will still assert, and that I am not beholden either to cocks or valves to obtain the perpetual motion I have discovered. When the world, or those philosophically wise in the world, are acquainted with its principles, they will wonder at its simplicity, and will say, as was said to lord Napier, when he invented the logarithms, "How is it we never discovered before that which is now so plain"?

Yours, with the greatest respect,
F. J-k-n.

WILLIAMSON'S IMPROVED LATHE. Feb. 16, 1824,

GENTLEMEN ;-Allow me to ask Charles Williamson what sort of line he uses to his lathe, and how he prevents the one part of the line from cutting or chafing the other? [See p. 369].

I have made the addition he so kindly points out to my lathe, and am of opinion, that it will answer every purpose, if the above difficulty (for such I have found it) can be got over. I put on a catgut line, and in ten hours wear, it was so reduced that it broke, although I varied the shape of the groove in the mandrel pulley six different times.

A WORKING TURNER.

INQUIRIES.

[All inquiries will in future be numbered, and the answers to them inserted in the numerical order of their application.] No. 1.-TREVETHICK'S ENGINE.

Salop.

GENTLEMEN ;-Should this meet the eye of some of your Cornish readers, resident in the neighbourhood of Truro, I should be much obliged to any one, competent so to do, if he would inform me, either through the medium of your publication, or otherwise, whether the Hydraulic Engine which was erected some years ago at the Druid Coppermine, in the parish of Illogan, near. Truro, by Mr. R. Trevethick, has fully answered its intended purposes. There are so many instances of practice falling far short of theory, even

under the auspices of the most ingenious, that I trust I shall not, by this inquiry, be supposed to call the abilities of the inventor into question. One objection to hydraulic engines on a large scale is the great degree of friction attendant on the working gear; but even with that objection, there are many opportunities for their advantageous application. A discussion upon this sort of engine is not, however, my present object; that which I seek to know is, whether the hydraulic engine of Mr. R. Trevethick, either at Illogan (or any other place where one may have been erected), has acquitted itself in such a manner as to render it deserving of adoption in situations where facilities present themselves for its application. I would also be glad to learn whether it winds as well as pumps, the depth to which it works, and if it often requires repair.

Hoping this may engage the attention of some of your readers, who may be kind enough to furnish me with the desired information,

I am, Gentlemen,

Yours very obediently,
GEO. E. HAMILTON.

No. 2.-BORING WELLS. The inhabitants of the low lands and marshes adjoining the river Wavenery (county of Suffolk) are often put to great inconvenience in summer from want of water, although their wells are usually sunk below the level of the bottom of the river, As far as I know, the banks are formed of four distinct strata:-1, a loose oozy alluvium, five feet deep; 2, A loose white sand, fifteen feet deep; 3, a close-grained bog earth, twelve feet, very black; 4, an earth resembling the last, but mixed with fine sand, and a few fragments of muscle and cockle-shells.

The uplands in the neighbourhood rise from 50 to 100 feet above the level of the river. In sinking wells, I have found no difficulty in getting down my brick-work five or six feet into the second stratum (a loose white sand); but at this depth the water from the land-springs becomes troublesome, and the sand falls in in such quantities, that the curb on which

the brick-work rests, will not settle downwards. From the bottom of a well, ten feet deep, I have lately bored thirty feet without finding any main spring: the soil being loose, it lies close to the borer, and has prevented me getting further down, although four hands were employed. When the borer is withdrawn, the aperture is immediately filled, and all our work must be gone over again.

Will any of your correspondents be so kind as to inform me, through the medium of your Magazine, by what mode I can reach the mainspring; if by pipe, what method ought to be used to get it down. As these wells are usually paid for by the foot, I have often been inadequately paid, owing to the time taken up in getting brick-work through this loose sand, which blows up nearly as fast as I can erect the brick

.

A CONSTANT READER, & A WELL-SINKER.

NORTON'S SPIRAL WHEEL. GENTLEMEN;-I had a model of a similar wheel to that invented by Mr. Norton, and noticed in your last, made about twenty years ago, and thought at first it would be useful in tide-mills. I accordingly tried it both ways, horizontally and vertically, but found the power so much less than that of the common waterwheel, on account of the greater friction caused by the water sliding along the screw, and the great pressure endways of the bearings, as well as the difficulty of keeping the water on the wheel without waste between the spiral floats and the casing (which was a complete cylinder), that I came to the conclusion that it could never be used to advantage. X. Y.

NEW PATENTS.

To Francis Devereux, of Cheapside, merchant; for certain improvements on the mill or machine for grinding wheat, and other, articles, commonly known by the name of the French Military Mill.8th January, 1824.

To Joseph Foot, of Charles-street, Spitalfields, silk-manufacturer; for an improved Umbrella.-15th January, 1824.

To John Finlayson, of Muirkirk, Ayrshire, farmer; for certain improvements on Ploughs and Harrows.—15th January, 1824.

To Jean le Grand, of Lemon-street, Goodman's-fields, vinegar manufacturer, for certain improvements in Fermented Liquors, and the various products to be obtained therefrom. Partly communicated to him by a certain foreigner residing abroad.-15th January, 1824

TO CORRESPONDENTS. We thank T.M. B.,for his suggestions. Veritas, who speaks not for himself alone, but "the sentiments of many," will find his queries partly answered by our account (in the Supplement) of the first Quarterly General Meeting of the Institution: we possess no other information on the subject. He had better apply to the Secretary, or to the Committee of Managers.

Communications in hand forinsertion of J. Y.-H. D.-H. T.-C. C.-W. K.J. B.

Communications received from J. S.T. B.- A Mechanic - No, MechanicPhilanthropus Alexander Brandt-T. J. Simpson-Son of a Mechanic-Journeyman Carpenter-G. J. Gurboss-A Constant Reader-C. H.-CombustionK. L.-G. R.-Specific-R. B.-John Goode-G. B.-Nauticus (whose proffered communications we shall be glad to receive)-X.-H.-W. Pennyston, Jun.-C. L. Y.-A. R. K.-Mesurage— and J. M.