J^otes to Introductolnj Lecture, 



Ixiii 



Rouelle in France and Mr. Brande in London, and their 

 agreement in the general result, leaves no doiiht as to the 

 accuracy of it. 

 Analysis of the camel's urine, as given by Mr. Home. 



95 



The urine of cows was also analyzed by both Mess. Brande 

 and Rouelle, both of whom agree in stating that potash is 

 the only fixed alkali in them. 



We now know that the salt which the ancients called sal 

 ammoniac f was common salt : and that the true sal ammoni- 

 ac is not found native. The Egyptians are stated to have 

 procured it by sublimation from soot of cow's or camel's 

 manure, urine and common salt : but from accounts trans- 

 mitted to the royal society at Paris, it appears certainly that 

 this salt is procured by sublimation from the soot taken alone 

 without any addition. Nicholson's Chemical Dictionary, vol. 

 1, p. 116 ; and 31agellan's edition of Cronstadt*s Mineralogy, 

 p. 4fb8, The soot taken from the chimneys in wbich cow 

 dung only, as fuel, is burnt, is said to furnish the best sal 

 ammoniac. This salt is however commonly prepared from 

 burnt bones, in the United States, and in Europe. 



From Vauquelin's analysis of the urine of various animals, 

 (Annales de Chimie, tom. 82, p. 197,) it appears that the 

 urines of the lion and the tiger are perfectly similar, and 

 differ from the human in some essential points. 



1. It is alkaline, even at the instant of being voided, and 

 hence its bad odour : while the urine of a healtby man is al- 

 wavs acid. 



