A A A A is a cistern of water, filled as high as B B. C C C C C C are six bladders, communicating by the tubes D D D D D D with the hollow axle E, which axle is connected with the bellows F by the pipe G. H is a crank connected with the crank I by the rod K. L is a saucer-wheel, M a pinion, N its shaft. O is a crank attached to the bellows F by the rod P. Q Q Q Q Q Q are valves with a projecting lever. R and S are two projecting knobs. T is a hole in the axle E, forming a communication with it and the lowermost bladder. The axle B being put in motion carried round the bladders and tables, and by the cranks H and I, and the connecting-rod K, caused the wheel L to revolve, which communicating a similar but accelerated motion to the pinion M, shaft N, and crank O, worked or blew the bellows F by the rod P; the air entered the axle E by the tube G, and passing through the hole in it at T, entered the lower bladder C by the tube D; this bladder being thus rendered lighter than the space it occupied, ascended, bringing the bladder behind it over the hole in the axle T in like manner, and which thereby gained an ascending power, producing a similar effect on the one behind it. When one of the bladders arrived at the knob S, the lever of the valve Q struck against it and opened the valve; when the bladder arrived at U and began to descend, its pressure on the water drove out the air and gave it a descending power; the knob R then closed the valve Q and prevented the entrance of any water into the bladder; by this contrivance three of the bladders were full and empty, according as they passed over the hole T or the knob S. George Cunningham's Mercurial Pneumatic Device. Ireland. 1729 [Illustration] Among the papers in the British Museum is one which purports to relate to the Royal Society, and in that Royal Society volume it is number 32. It is quite amusing. The author explains that he is withholding many precise details and measurements "such as workmen should follow in making the engine. Intending no more here than the endeavor to satisfy some others as well as myself, that there is really such a thing to be found as that long-sought for Perpetual Motion, which is looked upon by every one to be the true parent of the Longitude.--Description of the Perpetual Motion": A, a cup nearly full of mercury. B, the height the mercury will rise by its own weight in-- K, the main pipe, when-- C, the lower cock is open. E, a hollow globe which must be capable of a greater quantity than the whole pipe K. F, the upper cock by which the mercury is filled into the engine and about 27 inches higher than the line B. D, the middle cock which, when open, lets the mercury fall upon the buckets of the wheel-- G, and then passing down-- I, a funnel which contracts itself at L, into a pipe which directs the mercury into the cup A.