Foreign Literature and Science. 181 



and a spot of white foam appeared, the borders being in- 

 dented. This curious phenomenon continued one hundred 

 and fifty seconds. Ten drops formed a globule with hke re- 

 sults, except that it lasted two hundred seconds, and went 

 off without evaporation properly speaking, the spoon bemg 

 very hot. 



After these trials he used a capsule of pure silver and an- 

 other of platina, which were heated on coals to whiteness. 

 The phenomena were nearly the same. With the silver 

 capsule, in the first experiment 



the first drop continued 72 seconds, 

 the second - - 20 " 

 third - - 20 '• 

 fourth . . " 

 In the second experiment 



the first drop contmued 61 seconds, 

 the second - - 30 " 

 third - - 20 " 

 fourth . . 6 " 

 fifth - - " 



When there were three drops, the united ball continued 

 two hundred and forty seconds, and the evaporation was af- 

 terwards instantaneous. With the platina capsule, the first 

 drop continued fifty seconds, and a bubble of three drops 

 ninety seconds. — Ihid. 



26. Contents of rain water. — M. Liebig, professor of 

 chemistry at Geissen, found on an examination of seventy- 

 seven specimens of rain water, seventeen of which were 

 procured during storms, that the latter all contained nitric 

 acid in very different quantities, combined either with lime 

 or ammonia. Among the other sixty specimens he found 

 but two which contained a trace of nitric acid. 



The same chemist examined the residue of fifty other va- 

 rieties of rain water, collected by the late M. Zimmerman, 

 in 1821, 1822, and 1823; among them twelve contained ni- 

 trates. 



It thus appears, that during storms the azote and oxygen 

 of the atmosphere, combine and form nitric acid — a fact by 

 no means surprising, after the experimental results of Caven- 

 dish and Seguin. 



Hence when nitrates are found in materials which contain 

 neither animal nor vegetable matters, the acid is probably 

 formed by the electricity of the atmosphere. 



