gg' Hydraulics. — IVater-proof Clcth, 



good condition ; it is now dead (adds he), and preserved in 

 spirit of wme. It had two heads and two necks, conse- 

 quently four eyes, two mouths, two tongues, and two 

 throats; it ate with both its mouths, but as the will was 

 double, the ideas of the one head were independent of 

 those of the other, and often even they were in contra- 

 <liction. 



It is pot improbable that the fable of the hydra had its 

 origin from a serpent of this kind. The fondness of the 

 vulgar for \\ hatever is m.arvellous, induces tlieni to exagge- 

 rate every ihino- rare or extraordinary, and hence so many 

 fables and prodigies. 



tJYDRAULICS. 



Tht hvdraulic ram of M. Mongolfier has been con- 

 structed at Schaffhausen by counscilor Fischer in a very 

 3n"-enious n.anner. The machine has the form of a beau- 

 tiful antique altar, nca'-ly in the style of that of Ksculapius, 

 as reprcl^eatc(l in ditVerent engravings. A bason about six 

 inches in depth and from eighteen to twenty in diameter 

 receives the v.atcr, whicli enters into pipes three inches 

 in diameter, that descend in a spiral form into the base of 

 the altar. The water by its weight puts in motion a valvej 

 a third nearly of the water cscaper-, but the rest by the 

 pressure of the valve is forced into the receiver, and 

 thence rises in vcrv narrow pipes. As it ascends slowly 

 the resistance of the air makes no sensible impression, so 

 that by means of this machine, which continually acts by 

 jtself, water niay be conveyed from a lake or a river tc) 

 houses situated on a mountain. M. Fischer has conveyed 

 water bv it to a castle which stands atthe height of several 

 hundred feet above the level of the Rhine. 



AVATEU-PUOOF CI.OT^. 



It is well known that for some years past several methods 

 have been tried to render cloth impermeable to water, and 

 the invemors of this process have kept the discovery a mys- 

 tery. There was, hov/cver, reason to suppose that some 

 J'at oil made the basis of their recipes. A bottle of 

 this liquor, the efficacy of which was known, having fallen 

 bv chai'ce into the hands of M. Vauquelin, he was desirous 

 to discover the composition of it. The following is the 

 manner in which this chemist thinks it is composed, liaiing 

 the proportions. Soap and strong- glue, or any other ge- 

 latin, are disi^olved in water. With tliis solution is mixed 

 a solution of duni, which, being decomposed, forms in it 



a flaky 



