IMPROVED STEAM-ENGINE BUCKET, ETC. and stout frigates to recruit the navy? I now retire, for the sake of fair play, not because my heart is empty, And remain, Very respectfully, yours, June 27th, 1825. IMPROVED STEAM ENGINE BUCKETINUTILITY OF THE PAINTER'S REST WHICH GAINED THE ISIS MEDAL OF THE SOCIETY OF ARTS. SIR. Some years back, I was much inconvenienced in the working of a steam-engine of about thirty-five horse power, by not being able to get sufficient cold water to condense. My pump seemed to be too small, and the situation of the well, and other local circumstances, made it impracticable to have a larger pump, or to lengthen the stroke, without great expense and alteration. I consequently constructed a new sort of clack and bucket, whereby I thought more water could be brought up, well knowing that much water is lost through the ordinary clacks, and afterwards through the buckets, in bringing it up from the working part of the barrel or pump-tree. The result answered my most sanguine expectation. The vacuum I formed was stronger; the quantity of water I brought up was very considerably more than before, and for four years (since which I first adopted the plan) I have had plenty of water. I have shown the bucket to several scientific people, who all spoke very well of it. Continuing to find great benefit from it, I thought it, at last, a pity that it should not be made better known. I therefore made not only a communication of it to the Society of Arts, but mounted a six-inch bucket complete, which I sent to that learned body. The result was, that after it passed the examination of their Committee, no merit 207 was found in the contrivance, and I got my bucket back. This did not surprise me, because I am well convinced that man generally overrates his own talents; but what did surprise me, was, that the silver Isis medal was at the same time presented by the Society of Arts to a gentleman, for the invention of a Painter's Rest, to be used as a substitute for the common maul-stick. This said rest is upon the principle of a fire-screen, which vertically slides up and down.→ Now you must know, Mr. Editor, that in my younger days I was an amateur painter in the Netherlands; Mr. La Croix, of Bruges, was my instructor; and I was intimate with Solvyns, of Antwerp, and several other eminent painters of that day, and I venture to assert boldly, that the said painter's rest is totally unfit for its intended purpose, if the painting is to be of any size above a few inches. Sir Joshua Reynolds and Hickel (the latter I was personally acquainted with) would have laughed at this painter's rest; because the maulstick serves not only as a rest, but also as a lever of the second order. The fulcrum is at that end which, muffled, rests on the canvas or pannel; the rest of the arm is the weight, and by the power of the hand at the other end the rest is conveyed in all the necessary directions, which cannot be done with the aforementioned newly-invented rest, without constantly shifting the machine, and painting at the same time! The maul-stick performs another duty-it is a hold and rest for the hand that carries the pallet. I beg you to excuse this digression. To return to my bucket, I have only further to say, that its good qualities chiefly consist in this, that nothing can obstruct the entrance of the fluid, as in other large buckets. The entrance is clear and free; the clacks or doors, which are of brass, are so fitted as to make a perfect joint which holds water; and the longer it works, the closer these doors bed themselves. The gudgeons do not 208 RAPID EVAPORATION-GEORAMA, ETC.; work in a ring or filboa (as some I remain, Sir, Warrington, May 28th, 1825. [Ifour Correspondent could send us a good drawing and description of his improved bucket (to which we will readily give insertion), they would probably serve all the purpose of an actual inspection of the bucket itself. But should that be inconvenient, he will confer a favour by sending us the model, to the care of our Publishers.-ED.] RAPID EVAPORATION. Professor Ersted has pointed out a method of considerable utility in the evaporation of liquids. He fastens together a great number of fine metallic rods, or wire, and puts them in the bottom of the distillery or evaporating vessel, and by this means he distils seven measures of brandy with the same fuel, which, without the rods, would distil only four. GEORAMA. An establishment, under this title, has been erected in Paris, consisting of a hollow sphere forty feet in diameter, within which is laid out a general map of the world, executed by the best artists. A spiral staircase ascends to three circular and insulated balconies, whence the spectators can view every part of the sphere, even in its most minute details. Notices to our numerous Correspondents will appear in the next Number. Advertisements for the Covers of our Monthly Parts must be sent in to our 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. IMPROVEMENT ON THE LATHE, SIR,-Having Occasionally, in my leisure hours, amused myself with turning, I have noticed the difficulty there is in having the crank, that moves the wheel, of such a height, as to answer conveniently for turning both large and fine work. A high one gives power and ease in working, but is apt to affect the steadiness of the hand; a low one admits of a delicate and steady application of the tool to the work, but is inconvenient in turning any thing heavy, on account of the small purchase. It has occurred to me, that it might be possible to apply the eccentric circle, instead of the crank, to the purpose of turning the lower wheel of the lathe, and that it might combine the advantages of both a high and low crank, by making it to adjust at different degrees of eccentricity, so as to give a variety of powers, according to the purpose for which the lathe is at any time to be used. I enclose you a drawing that may serve to elucidate my meaning; observing, that I intend merely to give a hint, in hopes that some person more intelligent than myself in these things may think it worth improving on; that is, if the plan has never been before tried, of which I am igno rant, my usual occupation not leaving me time to penetrate very deeply into mechanical knowledge. I am, Sir, Your very humble servant, Walworth. Description of the Drawing. Fig. 1, a perspective view of the wheel and spindle, with eccentric circle affixed; the spindle is supported between centres in the usual way. A, the eccentric circle, of metal; the edge of it is cut into a deep groove. B, a screw and flanch, for the purpose of increasing or diminishing the eccentricity, thereby in creasing or diminishing the force, and rise of the treadle or foot-board. Ć, the foot-board. D, a pulley, grooved to correspond with the circle, and turning on centres; round it passes the flexible band, E, which communicates the motion to the circle and spindle, on pressure being given to the foot-board, which rises and falls in the usual manner. Fig. 2, a profile view of the same. Fig. 3, the circle, and a portion of the spindle separately exhibited. When the eccentric circle is in the position represented in fig. 2, if the footboard be pressed downward, it will be drawn in the direction AB, the wheel, D, turning on its axis at the same time; the force of the large wheel will then sition, when the pressure being repeated, carry it on till it returns to the first pothe motion will be continued, as by a common crank. 86 THE NEW DIVING APPARATUS." FORTY-SEVENTH PROPOSITION OF THE FIRST BOOK OF EUCLID. SIR,-Happening, a few days ago, to take up your excellent and scientific work, I opened it at the demonstration of this proposition, page 351, vol. III., and was surprised at the great inaccuracy and unmathematical mode in which this demonstration was proceeded in: but not having then time or inclination to go deliberately through the whole, I laid it down, reserving any comment I might make for some other opportunity, which opportunity has now arrived. On looking, therefore, at the figure as delineated (page 351), the postulata appeared well enough arranged for a practical demonstration; but when I proceeded to go through it, they did not reduce it to that mathematical certainty which alone is a proof of correctness. In the first place, the postulata (supposing the squares to have been previously drawn) appear to me to be incorrectly worded for the use to which they are afterwards put, or, rather, they are not the proper means used for cbtaining the required figure. In the second place, the referential letters are not arranged with the nicety they ought, showing at once the relative catenation of the argument; but, setting aside that, as well as the untechnical expres sions used throughout, I wili proceed to state, In the third place, that were you not to examine the figure, and ascertain that TM and EK are parts of DP and AK, and TE and MK are also parts of TG and MH, you could not possibly allow that ETMK was a parallelogram. In the fourth place, the line TD is equal to the line TE, not because it is the adjacent side of a parallelogram, but because it is so of a square. In the fifth place, the conclusion that the whole figure, KMPS, is equal to the whole figure, BTEC, is not proved from the premises set 211 forth; for we have no means of ascertaining from them, that the remaining sides, BC, CE, are equal to the remaining sides, MP, PS; and by no proposition of Euclid prior to this is it proved, that by having the four angles and two sides of one quadrilateral figure equal to the four angles and two sides of another, those two figures are of the same shape. This conclusion, therefore, having failed, it would be useless for me to proceed to subsequent ones. Remaining, however, à great admirer of your excellent work, I subscribe myself, Your obedient servant, 66 EDWARD. THE NEW DIVING APPARATUS." SIR,- Perceiving, in the 96th Number of your Magazine, an account of a new Diving Apparatus, by a person signing himself" T. B. of Leicester," I beg to say, that I have a patent, dated the 29th of May last, for an apparatus precisely similar in principle; and it is rather singular, that one of the first drawings I made of my invention also corresponds exactly, excepting in one or two trifling particulars, with the drawing your Correspondent has added to his particularly in his N. B., where he description; which also, in part, enters upon the calculation of the quantity of atmospheric air inhaled at one time, the number of inhalations per minute, the capacity of the vessel, the number of atmospheres condensed therein, the time a person may remain under water, &c. are, as near as possible, the quantities stated by me to Mr. Bate, optician, Poultry, London, more than two months ago. I likefore that time, to one of the Direcwise explained the principle, betors of the Pearl Fishing Company; and I have now been constructing the apparatus in Birmingham for the last six weeks. I described the invention, also, particularly to Mr. Wm. Newton, of Chancery |