Biographical Memoir of the lute Dr Turner. 239 



Turner's " Analysis of Edingtonite," another new mineral spe- 

 cies ;* but here his analysis was incomplete, owing to a deficiency 

 of material. 



A few months earlier he had published two successive papers 

 relative to the analysis of mica, and the occurrence of the alkali 

 lithia in this mineral. These were followed up early in 1826, 

 by a third on the same subject ; in which he proposes a new 

 method of detecting Lithia in the mineral kingdom. These pa- 

 pers have been considered by mineralogical chemists to be very 

 important in a practical point of view. In 1818, the alkali Li- 

 thia had been added to the list of true alkalis by the Swedish 

 chemist Arjicedson, and early in 18^5 Gmtlin announced the 

 discovery of it in a particular variety of mica. Soon afterwards, 

 Dr Turner, in his " Analysis of a Mica from Cornwall,"-f- whose 

 composition he determined with his usual accuracy, announced, 

 that he had found reason for concluding that lithia is a common 

 constituent of this mineral : and in a subsequent paper, " On 

 Lithion-mica^":}: he gives the analysis of three specimens in which 

 he had discovered the new alkali, explains a new process for se- 

 parating it from potash, and shews that lithia constitutes no less 

 than from two to four per cent, of the micas he had examined. 

 In his third paper on the same subject, namely, " On the means 

 of detecting Lithia in minerals by the Blowpipe,'''§ he shews 

 how its presence may be detected in any mineral by the red co- 

 lour imparted to the blowpipe flame, when the mineral is fused, 

 sometimes alone, sometimes witli a flux of fluate of lime. With 

 the preceding papers may be also arranged a fourth published 

 a few months later, being "an Analysis of two varieties of Le- 

 pidolite ;'"|| which he found to consist chiefly of silica, alumina, 

 potash, and fluoric acid, together with the same remarkable in- 

 gredient in the lithion-micas, viz. lithia in the proportion of 5^ 

 per cent. 



In the same year in which he finished these researches, he 

 brought forward another no less important paper in the same 

 department of chemical science, entitled, " On the detection of 

 Boracic Acid in Minerals by the Blowpipe." H He lure shews 



• Edin. Journal of Science, iii. 318. 1825. t Ibidem, iii. 137. 



t Ibidem, iii. 2C1. § Ibidem, iv. 113. 1C2C. II ILiJem, v. 162. 



182C. T Edinburgh rbilosophical Jouinal, xiv. 121. 182G. 



