Biograpldcal Memoir of the late Dr Turner. 245 



you the circumstances of liis last illness, which were in every re- 

 spect full of deep and affecting interest, and in one sense the 

 most instructive of all the incidents in his life. 



For some time after his appointment as Professor of Chemis- 

 try in London, he continued to exhibit the same untiring zeal 

 in the proniotion of his favourite science. In the year 1828 ap- 

 peared his " Analysis of Tabasheer," * an " Analysis of two 

 Hot Mineral Springs in India,"f his " Examination of a speci- 

 men of Native Iron from the desert of Atamaca in Peru,";]: and 

 the most elaborate of all his works, his " Chemical Examination 

 of the Oxides of ]Manganese."§ 



In his analysis of the Hot Springs of Pinnarkoon and Loor- 

 gootha in India, he proves that their solid ingredients are es- 

 sentially the same with those existing so remarkably in the 

 famous spouting fountains of Geyser and Rykum in Iceland, 

 namely silica held in solution by free soda. His investigations 

 on Tabasheer, the singular siliceous concretion often found in 

 the joints of the bamboo, were undertaken with the view of 

 clearing up the differences of opinion entertained by chemists 

 and physiologists in regard to its real source ; and he shows that 

 it consists of pure silica, with a trace of lime and vegetable 

 matter, but without any potash, which had been thought by 

 many to enter into its composition. Consequently the means 

 by which so large a quantity of silica is taken up and subse- 

 quently secreted by the plant, remains still a mystery in the 

 economy of vegetable life. The Atamaca iron-ore, the subject 

 of his third analytic paper for the same year, was sent in 1827 

 by Mr Woodbine Parish, the British Consul at Buenos Ayres, 

 as a specimen of a mineral which was found scattered in large 

 masses and numerous fragments over many leagues of country 

 in the province of Atamaca in Peru. Their structure favoured 

 the idea that their source was meteoric ; but their quantity in 

 this view appeared extraordinary. The inference from struc- 

 ture, however, was completely established by analysis ; for the 

 specimen proved to consist of metallic iron with six per cent, of 



* Edinburgh Journal of Science, viii. 3.35. 1«28, 

 + ILidein, ix. 95. 1828. + Ibidem, 259. 



§ Trans, of the Jloyal Soc. of Edinburgh, xi. 18.31. Read Dec. 182? 



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