Hydaulic Machine ai Schemnitt. 19 



afcerul and pafs through the pipes H into another rcfervoir I flill lower. The pipes N, 

 through which the fubterrancous waters are raifcd, are fixteen toifes in height. They 

 begin very near the bottom of the vellel I, in order that the air from that refervoir may not 

 efcape until all the water has been raifed. 



The pipes B and N are four and a half (French) inches in diameter within ; but thofe 

 H for the air are only three inches in diameter at ifluing from the refervoir D, and two and 

 a half when they enter the refervoir I, and this alfo is tlie diameter of the pipe P. 



The wooden trough L is the termination of a trough or channel from anotlier engine, 

 which raifes the waters from a yet greater depth. From this proceeds a pipe with a cock 

 K, in order that the water from L may either be admitted into I, or intercepted at pleafure. 



The refervoir D, which, as well as I, is ftiade of an alloy of copper and tin, is of double- 

 the capacity of I. It is eight feet and a half high, and five feet diameter infide meafure, 

 and its thicknefs is two inches. The lower refervoir I is four feet in diameter, and fix 

 feet and a half highinfide meafure, and its tliicknefs one inch and a half. Each of thefe 

 veflcls was caft in three pieces, as the drawing (hews, which arc joined by flanches and 

 fcrews, a ring pf lead and another of leather being placed between, to fecure the joint, and 

 prevent the tranfmifllon of any fluid. M. Jars obferrcs, that the pipes would have been 

 better if conne£ted in the fame manner } but the praftice is to drive the ends of the pipes 

 into hollow cylinders of very dry wood, iron bound with three hoops. Thefe anfwer very 

 Y'ell, and are of confiderable durability. 



The cocks C, E, K are fcrewed in their places by caps or covers faftened down with 

 fcrews. 



When the machine is to be put into a£lion, all the cocks are clofed, and as the refervoir 

 A is always full, the pipe B is alfo full, as far as the cock C. The refervoir L is alfo con- 

 ftantly full of water from the mine which is to be raifed fixteen toifes to O. For this purpofe 

 the cock K is opened, and the water flows into I, the air being fufFered to efcape from that 

 veflel by turning the cock M. The veflel is known to be full by the emiffion of water 

 through P J at which inftant both the cocks K and M are clofed. Immediately afterwards 

 the cocks C and G are opened, and the water from A entering B, comprefl'es the included 

 air, and forces it through the pipes H, where it prefixes on the furface of the water con- 

 tained in the inferior refervoir I, and forces that fluid to afcend through N to O, or the 

 Adit through which it is difcharged. This water being raifed, and the refervoir I being 

 empty, the cocks C and G are fliut, and E and F is then opened, the firft to fuflFer the con- 

 tents of D to flow off, and the fecond to accelerate the difcharge, by admitting the external 

 air. Both thefe cocks are again clofed as foon as the evacuation is completed. During 

 this laft operation, another man below opens the cocks K and M, by which the included air 

 ifiues with great force through P, and the water from L again fills the refervoir I as at firft. 

 The operations of doling K and M, and opening C and G, being therefore again repeated, 

 the contents of I are again forced up to, and thus the engine may be kept continually 

 at work. 



D' z Each 



