208 RAPID EVAPORATION-GEORAMA, ETC. work in a ring or filboa (as some I remain, Sir, D. 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 Publishers before the 20th of each Month. 1 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. 210 IMPROVEMENT ON THE LATHE. Fig 2. E Fig.3. 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 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 increasing or diminishing the force, and rise of the treadle or foot-board. C, 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 carry it on till it returns to the first position, when the pressure being repeated, the motion will be continued, as by a common crank. 66 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 obtaining 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 expressions used throughout, I will ceed to state, pro 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, a great admirer of your excellent work, I subscribe myself, Your obedient servant, 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 description; which also, in part, Correspondent has added to his particularly in his N. B., where he 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 212 HORIZONTAL WHEEL-NEW CHURNING MACHINE. lane, more than three months ago, and made an affidavit of the invention before a Master in Chancery, on the 26th of March last. I can likewise prove, by witnesses of the highest respectability, that I fully described the same to them more than twelve months since. If your Correspondent, therefore, has received the idea from others, I hope he will have the candour to acknowledge the same; if, on the contrary, they have originated with himself, I have only to say, it is a most singular coincidence of thought. You will oblige me by mentioning another part of my invention, which my patent includes, the title of which is as follows:-"For certain improvements in apparatus for diving under water, the whole or part of which apparatus is applicable to other purposes." I apply part of the same apparatus to the propelling of carriages and vessels, by the expansive power of atmospheric air in a condensed state. I constructed a carriage on this principle more than a year ago, which was exhibited in motion to a few individuals, and was found to answer their most sanguine expectations. I have not hitherto brought it before the public, on account of the difficulty of constructing a hollow vessel of sufficient strength to contain the necessary quantity of atmospheric air in a condensed state, without being too heavy and cumbersome for the convenience of locomotion. Having now accomplished this object, I expect shortly to have it in my power to construct carriages which will move by the before-mentioned power of condensed air; and which (should they on trial be found to succeed) will, in point of safety, economy, expedition, and convenience, probably exceed any other kind of carriages now in use. My patent has other applications of minor consideration, which, of course, will shortly appear in my specification. W. H. JAMES. Winson Green, near Birmingham, HORIZONTAL WHEEL-NEW CHURN- SIR, I learn by a communication from New York, that the Rev. Dr. Phoebus, of that city, has constructed a Horizontal Wheel, to be propelled by the wind, the plan of which is extremely simple. There are eight horizontal rays or booms attached to a perpendicular shaft, and on these booms as many sails (in form of a jib) slide out by rings as on the masts of a vessel; each sail is then belayed or fastened (from right to left) to the front ring or travelles of the left-hand sail; and they are suspended so far below the booms as to receive the full impression of the wind-all horizontally. In the revolution of this wheel, it will be readily perceived that the sails turn their backs (or booms) to the wind upon the one side, and form no impediment to the full force of the breeze upon the other side; and they slide out and in with so much convenience, that any length of the sails may be extended at pleasure, or the whole tucked up close at the centre. One, two, or more of these wheels may be attached to the same perpendicular shaft; and it is hardly necessary to say, that they may be applied to almost every description of machinery. The wings or sails may be formed at pleasure, either of canvas, as above mentioned; or, agreeable to Hooper's plan, to open on rollers; or, on the late improvements of Forman's plan, made of thin sheetiron, to open and close like a Venetian blind. Another useful invention, which has made its appearance in America, and which, like the former, is the work of a clergyman (the Rev. Mr. Wilmott, of Wilton), is a new Churning Machine, which, for ease and expedition, and the quantity and quality of the butter, is believed to excel any thing of the kind heretofore in use. The body of the churn is square at the bottom; the two opposite sides are perpendicular; the other two op |