George Cunningham's Mercurial Pneumatic Device. Ireland. 1729
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.
H, a case which entirely covers the wheel (being of the same metal, and of a piece with the pipe), through which the axis of the wheel passes to set another wheel agoing; so becom [ing] the principal mover in the clock or engine to be contrived.
The Manner of Setting It to Work
Stop the cock at C and fill mercury into the cup A, higher than the line B; then stop the cock at D and turn in mercury at the cock F, till K and E are full; stop the cock at F, very close, open C, first, and then D, out of which the mercury will fall upon the buckets of the wheel G, down the funnel I, L, into the cup A, and be pressed up K, by the weight of the air, as in the barometer.
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.
H, a case which entirely covers the wheel (being of the same metal, and of a piece with the pipe), through which the axis of the wheel passes to set another wheel agoing; so becom [ing] the principal mover in the clock or engine to be contrived.