Substances communicate to the Flame of the Bloz&pipe. 343 



lour, these are Strontian, lime, and lithion. The shade is that 

 of deep carmine. 



Carbonate and sulphate of Strontian present at the first mo- 

 ment a feeble atmosphere, which is presently replaced by a 

 beautiful red, which is permanent. The mixture of barytes 

 makes the reaction of the Strontian disappear. 



Iceland spar and arragonite give a colour somewhat less in- 

 tense than that produced by Strontian, as soon as the carbonic 

 acid is expelled. The impure limestones and dolomites do not 

 colour the flame red, or colour it but very feebly. Fluorspar 

 gives an intense red colour ; sulphate of lime produces but a 

 weak one ; and phosphate and borate of lime do not give rise 

 to it. 



When there is barely introduced into the blue flame an aci- 

 cular fragment of a substance which contains lithion, immediate- 

 ly after fusion, their appears a purplish red streak of great in- 

 tensity ; but the colour quickly disappears, and does not recur 

 unless there be introduced into the flame a particle of the assay 

 piece which has not yet been heated. The petalite of Uto, 

 which contains much lithion, yields, however, but a very feeble 

 red. 



The outer flame of the blowpipe is rendered pale blue by 

 arsenic ; a little deeper by antimony ; and beautiful sky-blue by 

 lead. With antimonial galena, the blue is at first pale, and af- 

 terwards becomes sky-blue. 



I am acquainted with only three substances which give a 

 green colour to the flame : they are boric acid, barytes, and 

 oxide of copper. 



Boric acid, natural or artificial, yields a fine green. Borate 

 of lime, datolite, and botryolite, give a less distinct green co- 

 lour. Borax produces a strong reddish atmosphere, and only 

 shews the green colour when it has previously been sprinkled 

 with sulphuric acid. 



To discover the presence of boric acid, I have tried the flux 

 described by Ur Turner, which is composed of fluate of lime 

 and bisulphatc of potash ; but these trials did not succeed, pro- 

 bably from want of habit. Be this as it may, all the minerals 

 mentioned by Dr Turner, as colouring the flame green on being 

 mixed with his flux, have yielded me the same re-action on be- 



