Chemistry and Physics. 417 
Lnthium.—The ignited vapor of lithium compounds exhibits two sharply 
defined lines, a very faint yellow line Lic, and a brilliant red line Li &. 
The former lies between Fraunhéfer’s lines, © and D, but nearest to D— 
the latter lies between B and C. e reaction is somewhat less sensitive 
than that for sodium, perhaps because the eye is more sensitive to yellow 
than to red rays. The authors find that less than y,598,yp of a milli- 
gramme of carbonate of lithia ean be detected with the greatest cer- 
Minerals containing lithia like triphyllin, triphane, petalite, ete., require 
only to be held in the flame in order to give the most intense line Li 
th . 
delicate ; only about zoo of a milligramme of potassium can be ren- 
dered visible in this manner. ee ek 
All the volatile compounds of potash exhibit this reaction: silicates 
istic lines, To detect extremely slight traces of potash, the silicate must 
AM. JOUR. SCIL—SECOND SERIES, Vor. XXX, No. 90.—NOV., 1868. . 
53 
