326 Spectwscojnc Examination of Silicates. 



for calcic chloride, in order to get rid of the calcium 

 spectrum ; but this reagent was not powerful enough to 

 efiect decomposition. The results which may be obtained 

 with baric and strontic chlorides, etc., are still to be looked 

 for. It should be remarked that no acid vapors are set free 

 by this process, and that the spectroscopist may work for 

 hours in a dark room, without injury to himself or his ap- 

 paratus ; which he could not do if the mineral were mois- 

 tened with hydrochloric or other acid. 



To speak of the results thus far obtained, I would say 

 that many minerals which have been reputed to contain 

 alkalies, have revealed this fact when tested by the calcic 

 chloride process, and that many others in which the alkalies 

 have previously escaped detection, have manifested them in 

 the most striking manner. It is very noticeable, when 

 rocks and minerals are treated in the manner described, 

 that lithium, in minute quantities, is not a rare but a vety 

 common element. Thus, for example, a light greenish 

 muscovite from Dixon's Quarry, near Wilmington, Del., 

 contains lithium as well as potassium and sodium. In the 

 list of analyses of muscovites which is cited in Dana's 

 Mineralogy (5th ed., p. 310 and 311), it will be seen that 

 only two muscovites are reported as lithium-holding. One 

 is a rose colored mica from Goshen, Mass., which was ana- 

 lyzed by Prof. Mallet, and contains 0-64 per cent, of 

 lithium. The other is a mica from Orange Co., N. Y. 

 (the analysis cited differs very widely from that of a nor- 

 mal muscovite), and contains 0-06 per cent, lithium. 



One of the varieties of fibrolite, known as bucholzite, 

 which occurs as a silky-white coating upon the gneiss rocks 

 bordering the Schuylkill river in the vicinity of Philadel- 

 phia, gives with calcic chloride, both potassium and lithium 

 bands. None of the fibrolites, nor any of its varieties, silli- 

 manite, monrolite, xenolite, worthite, have ever been re- 

 ported to contain alkaline metals, except a specimen of bu- 

 cholzite, analyzed by Brandes (Jour, de Pharm., XCI, 237), 



