METHOD OF RAISING WATER. ^\ 



are required to produce one pound of leather, it appears, from 

 the various fynthetical experiments, that about half a pound of 

 catechu would anfwer the fame purpofe *. 



Alfo, allowing for the difference in the compofition of the Its comparative 

 different kinds of leather, it appears, iiom the gene.al detail of 

 fads, that one pound of catechu, for the common ufes of the 

 tanner, would be nearly equal in value to 2i pounds of galls, 

 to 7y pounds of the bark of the Leicefter willow, to 1 1 pounds 

 of the bark of the SpaniflVchefnut, to 18 pounds of the bark of 

 the elm, to 21 pounds of the bark of the common wiilow, and 

 to3 pounds offumach. 



Various menllruums have been propofed for the purpofe of Lime and other 

 ,. , . . , r r . ■ 1 n additions are 



expediting and improvuig the procels of tannmg, and, amongft pj-obabiy hurt- 

 them, lime-water and the folutions of pearl-a(h : but, as thefeful. 

 two fubdances form compounds with tannin which are not de- 

 compoikble by gelatine, it follows that their effeds inuft be 

 highly pernicious ; and there is very little reafon to fuppofe, 

 that any bodies will be found which, at the fame time that they 

 increafe the folubility of tannin in water, will not likewife di- 

 miniflj its attradion for ikln. 



vr. 



An eafy Method of raifing Water for the Purpnfes of Refrigeration 

 in DifuUeries, Steam Condenfers, &c. Bi/SiK A. N. Edejl- 

 CRANTZ. Communicated by the Inventor. 



1 HE method exhibited in the fketch, Pig. II. Plate IV. Introduaios. 

 being capable of faving near thirty feet of the height to which 

 water may be required to be pumped, for the ufes mentioned 

 in the title, appeared too fimple and ingenious, when the learn- 

 ed inventor did me the honour to mention it In converfation, 

 for me not to require permilTion to communicate it to my 

 readers. 



* This efiiimation agrees very well with the experiments lately 

 made by Mr. Purkis, upon the tanning powers of Bombay catechu 

 in the procefTes of manufnfture, and which he has permitted me to 

 mention. Mr, Purkis found, by the relults ot different accurate 

 experiments, that one pound of catechu was equivalent to feven or 

 eight of oak bark. 



3 If 



