CONTRIBUTIONS TO BLOWPIPE ANALYSIS. 341 



— unless the latter substance be present in traces only — may be safely 

 concluded.* 



2. METHOD OF DISTINGUISHING THE EED FLAME OF 

 LITHIA FROM THAT OF STRONTIA. 



[First published in the Chemical Gazette: May 1, 1848.] 



It has been long known that the crim.son coloration imparted to the 

 blowpipe flame by strontia, is destroyed by the presence of baryta. 

 This reaction, confirmed by Plattner — see, more especially, the 

 third edition of his Probirkunst, page 107 — was observed as early 

 as 1829 by Butzengeiger {Annates des Mines, t. y.,p. 36). The 

 latter substance, however, as first indicated by the writer, does not 

 affect the crimson flame-coloration produced by litbia. Hence, to dis- 

 tinguish the two flames, the test-substance may be fused with 2 or 3 

 volumes of chloride of barium in a loop of platinum wire, the fused 

 mass being kept just within the point or edge of the blue cone. If the 

 original flame-coloration proceeded from strontia (or lime), an impure 

 brownish -yellow tinge will be imparted to the flame-border ; but if the 

 original red colour were caused by lithia, it will not only remain unde- 

 stroyed, but its intensity will be much increased. 



This test may be applied, amongst other bodies, to the natural 

 silicates, Lepidolite, Spodumene, &c. It is equally available, also, in 

 the examination of phosphates. The mineral Triphylline, for example, 

 when treated per se, imparts a green tint to the point of the flame, 

 owing to the presence of phosphoric acid ; but if this mineral be fused 

 (in powder) with chloride of barium, a beautiful crimson coloration in 

 the surrounding flame-border is at once produced. 



* In testing this method, a mixture was prepared of 2 parts of ignited carbonate 

 of soda with 1 part of carbonate of lithia, and portions of this were placed in six 

 little porcelain capsules, distinguishing upon their undersides by a spot of ink ; 

 whilst into six similar but unmarked capsules, some carbonate of soda, only, was 

 placed. The capsules being then arranged indiscriminately upon a tray, each 

 was separately examined, and it was found that those which contained lithia 

 could be separated from the rest without the slightest difiBculty (November, 1850). 

 This plan was repeated with equal success, on mixtures of 3 (NaO, CO^) + 

 1 (LiO, CO^), and 6 (NaO, CO^) -i- 1 (LiO, CO^), in May, 1865. When the 

 lithia is in very small quantity, the blowpipe flame must not be too large. 



