412

SIR,-It has for some time been an object with me to obtain some authentic account of the number of Mechanics' Institutions, and Mechanics' Book Clubs, now existing in different parts of the country; and it has just occurred to me, that your very useful Magazine might be made the means of obtaining this most desirable information, by introducing a notice, inviting the Secretaries, or other Officers of such Institutions, to forward to the Editor the names of the societies to which they belong. To communicate, however, to such a return all the advantages of which it is susceptible, it would be most desirable to include in it the number of members belonging to each society, the average number of readers which attend the libraries or reading rooms, the number of volumes of which each library consists, and the rate of the weekly or annual contributions, brought up to some definite period, say Michaelmas, 1825. Such returns, when collected by the Editor, might be tabulated and reduced into a systematic form, and printed in the Mechanics' Magazine; thus affording the materials of much important information, not only to the present generation, but to the historian, whose duty it may be, in after ages, to trace the causes that have operated in accelerating the march of useful information among the working classes. And if annual returns of the same kind could be made, and tabulated according to the best form, the successive steps which mark the growth and extension of mechanical information might be traced from year to year, and from one generation to another.

To your most useful Magazine, dedicated so exclusively in its objects to the diffusion of sound mechanical information among the operatives-the most numerous class by far of our active and enterprising community-the future investigator of the causes of our unrivalled superiority in arts and manufactures will naturally turn, for the materials to assist him in his magnificent survey. Few surveys, indeed, could present more striking and impressive results. It would interest both the philanthropist and the philosopher; it would form a sort of skeleton map of the state of useful knowledge among the operative classes, which every year would tend to beautify and fill up.

For want of authentic information of this kind, if we attempt at any time

to trace the causes that have led to

results so interesting to human happiness, as are daily presented to our contemplation, we soon become enveloped in uncertainty and error. Let us, however, hope, by the attention that has been latterly awakened to statistical inquiries in this country, that our successors may not have occasion to say of us, what we sometimes have good occasion to say of our predecessors. Let us remember, "that it will equally reflect on the present generation, when they, like the former, shall become the past, unless some means are adopted to furnish our successors with those interesting facts, the want of which leaves us often enveloped in the shades of uncertainty and error.*” I remain, Sir, Your obedient servant, GEORGE HARVEY, F.R.S. Plymouth, Sept. 21st, 1825.

1

P.S. The reader is requested to mark with inverted commas the 11th, 12th, 13th, and 14th lines, from the bottom of the second column of the Letter in page 315; and also the 19th, 20th, and 21st, and the five concluding lines of the second column of page 316.

*Wimpey on Economical Registers, vol, I. Manchester Memoirs.

ANNUAL RETURNS OF MECHANICS' INSTITUTIONS.

413

STATE OF THE

MECHANICS' INSTITUTION (OR BOOK CLUB), FOUNDED (insert here the period), AT MICHAELMAS, 1825.

SIR-The above figure is intended to represent a Section of a Pump, whose pistons, however large, have no friction.

AAA represent the pump, consisting of three distinct cylinders, screwed together by their flanches, BBB, screwing in also leather long enough to descend inside-say here six inches; the other end of this leather, CCC, to be nailed round a piston of wood, having a valve in its centre, D, opening upwards; two or more working rods, EEEE, pass through and hold each piston, as they move up and down together by the action of the pump-handle, FF. It is manifest,

that the leather round the edge of the piston, though only six inches long, will make a 12-inch stroke, because it passes from six inches below to six inches above the junction of the cylinders, whose parts at the flanches are made larger for that purpose, which allows the leather to move freely, and also the capacity of the pump to be increased, without increasing the bore of the other parts. Suppose this pump 18 feet high, and the pistons six feet asunder, then, during the lift, the leather would have rather less than 3lb. pressure to each square inch, because the column of water, 18 feet

high, is divided into three parts, and each piston lifts only six feet; the lower one, near the bottom valve, G, lifts rather more, in proportion to its distance from it. The lower flanch must be air-tight, the others water-tight, these latter being merely water-lifters. I think leather suffi

ciently pliant may be found that would lift 61b. to each square inch; in that case the cylinders may be 12 feet long each; however that may be, it is obvious that, by increasing the number of these cylinders and leather bound pistons, both the height and capacity of the pumps may be increased, without producing any friction; and by making the valve-holes at D large, any floating rubbish would pass upwards, at the moment the pistons were at their highest point, and just opened to return. If the leather were cut out of a whole skin, no sewing together would be necessary.

I am, Sir,
Your obedient servant,

415

Now, if the resistance be 1, and the velocity 1, what will be the ratio of resistance when the velocity is 2, 3, 4, 5, 6, 7, 8, 9, 10, and so forth? and, further, would any other figure than a sphere, or material than cast-iron, commencing with the same relations (1 to 1), give a different ratio of resistance. What would be the difference, and the cause of the difference?

Should any of your Correspondents favour me with accurate information upon this subject, or direct me to a source from whence I may derive it, I shall feel much obliged. I am, Sir, Your most obedient servant, AQUARIUS.

NO. 157.-BRONZE COMPOSITION.

SIR,-Permit me to inquire of some of your intelligent Correspondents, what is the best Composition for what is called, amongst brassfinishers," Bronze," for giving to brass-work the appearance of real bronze metal, and, at the same time, the proper method of treating the brass-work with it. From the different specimens of work of this kind which I have seen, varying from the perfect black to the light green shade, it occurs to me, that there must be different compositions for producing the various colours, and, probably, different ways of using the compositions. Any information on this (to me) interesting subject will be highly esteemed by,

Sir,
Yours respectfully,

Newcastle-upon-Tyne.

H. S.

416

NEW PATENTS.

M. Poole, Lincoln's Inn; for the preparation of certain substances for making candles, including a wick peculiarly constructed for that purpose.-June 9.

J. Burridge, Nelson-square, Blackfriars-road, merchant; for improvements in bricks, houses, or other materials, and for the better ventilation of houses and other buildings.-June 9.

J. Lindsay, of the island of Herme, near Guernsey; for improvements in the construction of horse and carriage ways of streets, turnpike and other roads, and an improvement or addition to wheels to be used thereon.-June 14.

W. H. James, Coburg-place Winsongreen, Birmingham, engineer; for improvements in the construction of boilers for steam-engines.-June 14.

J. Downton, Blackwall, shipwright; for improvements in water-closets.June 18.

W. Mason, Castle-street, East, Oxford-street, axletree-manufacturer; for improvements on axletrees.-June 18.

C. Phillips, Upnor, Kent; for improve ments in the construction of a ship's compass.-June 18.

G. Atkins, Drury-lane, and Henry Marriott, Fleet-street, ironmonger; for improvements on, and additions to, stoves or grates.-June 18.

E. Jordan, Norwich, engineer; for a new mode of obtaining power applicable to machinery of different descriptions.

June 18.

J. Thompson, Vincent-square, Westminster, and the London Steel Works, Thames Bank, Chelsea, and John Barr, Halesowen, Birmingham, engineer; for improvements in producing steam applicable to steam engines, or other purposes.-June 21.

T. Northington, the younger, and J. Mulliner, both of Manchester, smallware manufacturers; for improvements in the loom or machine used for the purpose of weaving or manufacturing of tape, and such other articles to which the said loom or machine may be applicable.-June 21.

Ross Corbett, Glasgow, merchant; for a new step or steps to ascend and descend from coaches and other carriages. June 21.

P. Brookes, Shelton, in the Potteries, Staffordshire, engraver; for improvements in the preparation of a certain composition, and the application thereof, to the making of dies, moulds, or matrices, smooth surfaces, and various other useful articles. June 21.

NOTICES

ΤΟ

CORRESPONDENTS.

An Amateur says, that if "D. J. (Inquirer 144) will describe the intended application and use of the Lens he wishes to grind, he will endeavour to give him the information he requires." "In the meantime," he adds, "I shall be glad to be informed if there is any book to be got which gives a description of the construction of Telescopes of all kinds, and which treats of their sizes, magnifying powers, uses, and qualities, as compared with each other; with historical remarks on some of the most famous that have been made, as well as on the makers. Dr. Kitchiner has long promised something of this kind; and should this meet his eye, I hope he will favour me, and your readers in general, with his intentious on that subject, and let us know how long it will be before it be published, as I have several friends who are anxiously expecting it, and who, with myself, will take a copy each."

The request of our friends at Cardigan shall be complied with.

.

H. H. H. will find that water alone, and water colours, are sufficient.

"An Old Toper" cannot do better than put his plan into practice. We think it good, and shall be glad to know the result.

Communications received from-Robert Edwards-Ikey Pringle-C. Y. J.Libra-Philarchus-A Member of a Mechanics' Institution in Kent-D. P. S.B. B.-Nemo-An Old Horse--John Simpson-Rachel-P. R. E. S.

Advertisements for the Covers of the Monthly Parts must be sent to the Publishers before the 20th day of each Month.

Communications (post paid) to be addressed to the Editor, at the Publishers', KNIGHT and LACEY, 55, Paternoster-row, London. Printed by Mills, Jowett, and Mills (late Bensley), Bolt-court, Fleet-street.