Observations of Dr Papin, Fellow of the Royal Society, on a French Paper concerning a Perpetual Motion

Observations of Dr Papin, Fellow of the Royal Society, on a French Paper concerning a Perpetual Motion. The Paper printed in French and containing a contrivance for a perpetual motion, being set down in such a manner, that can hardly be understood but by those that are much acquainted with such descriptions: I have endeavoured to explain it as follows. Let DEF Fig. 9. be a pair of bellows 40 inches long, that may be open'd by removing the part F from E: let them be exactly shut everywhere but at the aperture E; and let a pipe EG, 20 or 22 inches long, be soldered to the lay'd aperture E, having its other end in a Vessel G, full of Mercury, and placed near the middle of the bellows. A, Is an axis for the bellows to turn upon. B, A counterpoise fastened to the lower end of the bellows. C, A weight with a clasp to keep the bellows upright. Now if we suppose the bellows open'd only to $\frac{1}{3}$ or $\frac{1}{4}$ standing upright as Fig. 9th. and full of Mercury, it is plain that the lay'd Mercury being 40 inches high, must fall, as in the Torricellian experiment, to the height of about 27 inches, and consequently the bellows must open towards F and leave a vacuity there: this vacuity must be fill'd with the Mercury ascending from G through the Pipe GE, the lay'd Pipe being but 22 inches long: by this means the bellows must be opened more and more till the Mercury continuing to ascend makes the upper part of the bellows so heavy, that the lower part must get loose from the clasp C, and the bellows should turn quite upside down; but the Vessel G being set in a convenient place keeps them horizontally as Fig. 10, and the part part $F$ engageth there in another Clasp $C$; then the Mercury by its weight runs out from the bellows into the Vessel $G$ through the Pipe $EG$, and the bellow's must shut closer and closer until the part $EF$ comes to be so light, that the counterpoise $B$ is able to make the part $F$ get loose from the clasp $C$; then the bellows come to be upright again as Fig. 9th; the Mercury left in them falls again to the height of 27 inches, and consequently all the other effects will follow as we have already seen, and the motion will continue for ever. Thus much the French Author. Upon this it is to be observed, that the bellows can never be opened by the internal pressure, unless the said pressure be stronger than the external: now in this case the weight of the Atmosphere doth freely press up the outward part of the bellows, but it cannot come at the inward part but through the Pipe $GB$, which containing 22 perpendicular inches of Mercury, doth counterpoise too much of the weight of the Atmosphere, so that this being supposed to be 27 inches of Mercury, it cannot press the inward part of the bellows but with a weight equivalent to 5 perpendicular inches of Mercury. From this we may conclude, that the pressure of the Atmosphere being weakened within the bellows, more than it can be helped by the Mercury contained in the same, as may easily be computed; the said bellows standing upright as Fig. 9th, must rather shut than open. Thus, without loosing any labour and charges in trying, people may be sure that the thing can never do.