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 workingrods, 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 sufficiently pliant may be found that would lift 6lb. 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,

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 Inu; 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 intenhow long it will be before it be published, tious on that subject, and let us know 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-Ro bert 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.

No. 111.]

[Price 3d.

SIR, Th following is a description of the new mode of firing rockets (by steam), invented by Mr. Perkins, for which he has obtained a patent.

Fig. 1 shows a section of the rocket or hollow vessel (made of wrought iron), which is to contain the water. A piece of iron, B, is screwed into the end of this vessel, having, a small aperture or bore extending through it. To this piece the tail of the rocket, with the guide-rods, CC, in lieu of the usual rocket-stick, is attached; and the vessel being completely filled with water to a short distance up the aperture or bore, a plug of brass is to be driven into the bore, which confines the water within under considerable pressure.

VOL. IV.

The rocket is now to be placed in the furnace, as shown at fig. 2. A cylinder, DD, made of cast-iron, and open at both ends, is to be built into the furnace in an oblique direction, for the purpose of receiving the rocket; which cylinder, becoming red hot, will communicate its heat to the rocket placed therein, and when the heat has caused the brass plug (which closes the bore of this pipe, 6) to melt, the force from within will drive it out, and the water also, which, immediately flashing into steam, will cause the rocket to be propelled forward in the direction of the cylinder, DD, which is its guide. The plug may be made of other metals instead of brass, or such alloys as will melt at given tempera

2 E