34^ CONTRIBUTIONS TO BLOWPIPE ANALYSIS. 



years — together with two other applications of the blowpipe, published 

 here for the first time, but already shewn to several persons interested 

 in this method of research. Some of these tests have been appro- 

 priated by certain authors without the slightest acknowledgement ; 

 others have been incorrectly quoted ; and some, again, appear to have 

 escaped the attention of the editors of several recent works in which 

 the applications of the blowpipe come under review. These reasons 

 have led the writer to republish them, in the present place, in a 

 condensed form, preparatory to the issue of an extended work on 

 Blowpipe Practice, in which various new tests, and a large amount 

 of other original matter, will be incorporated. This work will appear, 

 it is hoped, early in 1806. 



1. DETECTION OF LITHIA IN THE PRESENCE OF SODA. 



[First published in the Chemical Gazette : November 15, 1850.] 



This test may be applied to mixtures of these alkalies in the simple 

 state, or to their carbonates, sulphates, nitrates, or other compounds 

 capable of being decomposed by fusion with chloride of barium. The 

 test-substance, in powder, is to be mixed with about twice its volume 

 of chloride of barium, and a small portion of the mixture is to be 

 exposed on a loop of platinum wire to the point of a well-sustained 

 oxidating flame. A deep-yellow coloration of the flame-border, pro- 

 duced by the' volatilization of chloride of sodium, at first ensues. 

 This gradually diminishes in intensity, and after a short time, a thin 

 green streak, occasioned by chloride of barium, is seen to stream from 

 the point of the wire, as the test-matter shrinks further down into the 

 loop. On the fused mass being then brought somewhat deeper into 

 the flame, the point and edge of the latter will at once assume the 

 rich crimson tinge characteristic of the presence of lithium compounds; 

 and the colour will endure sufiiciently long to prevent the slightest 

 chance of misconception or uncertainty. The presence of strontium 

 compounds does not afl'ect this reaction, as these compounds, when 

 fused with chloride of barium, cease to impart a red color to the flame 

 (see No. 2). In order to ensure success, or rather to avoid the least 

 risk of failure, in the application of this test, it is only necessary to 

 keep up a clear and sharply-defined flame for about a couple of minutes. 

 ,If the red coloration do not appear by that time, the absence of lithia 



