Dr Turner on Lithion-Mica. 269 



make such observations at night, or in a dark room ; and a 

 wax candle, from the pure whiteness of its light, is best fitted 

 for them. 



While engaged in this inquiry, it became necessary to as- 

 certain what effect the sulphates of potash and soda would ex- 

 hibit under similar treatment, and I was thus led to an obser- 

 vation of some interest, and which to me is new. When a 

 crystal of Glauber salt is put into the flame of a candle, and 

 more particularly when made to touch the wick, the flame it- 

 self enlarges considerably, and becomes of a decidedly yellow 

 colour. When the powdered sulphate of potash, well moist- 

 ened, is treated in like manner, the candle burns with a pale 

 violet-coloured light, without enlargement of flame. These 

 salts do not produce their characteristic effect when used in 

 very small quantities like the sulphate of lithia. The effects 

 here ascribed to the sulphates of potash and soda, may also 

 be procured with the carbonates and muriates of those alka- 

 lies. 



There is no doubt, therefore, that the three alkalies, potash, 

 lithia, and soda, may readily be distinguished from one ano- 

 ther by their action on the flame of a candle. 



From the result of the analyses contained in the present pa- 

 per, together with the foregoing observations, it is certain that 

 the lithion-micas owe their property of reddening the blow- 

 pipe flame to the presence of lithia, and that this phenome- 

 non is consequently a proof of the presence of that alkali in 

 them. 



It would appear from the facts just detailed, that a body 

 must be fluid in order to produce an effect in colouring flame. 

 The insoluble salts of lime and strontia are quite inert, as are 

 the soluble salts of lime, strontia, and lithia, when quite dry. It 

 is perhaps from their easy fusibility that the lithion-micas owe 

 their power of reddening the blow-pipe flame, while other li- 

 thion-minerals, as spodumeneand petalite, which are of difficult 

 fusibility, do not possess that property. It would follow from 

 this, that by mixing some flux with spodumene, so as to render 

 itfusible, it should acquire the property of tinging the flame red; 

 and if so, an easy and expeditious method might be discovered 

 of ascertaining the presence or absence of lithia in any mineral 



