240 Biographical Memoir of the late Dr Turner, '] 



that, by means of a flux of fluate of lime and bisulphate of po- 

 tash, boraclc acid may be discovered in the minute proportion 

 of 1 per cent, in a mineral, by the green light communicated to 

 the blowpipe flame ; and he proves by this method the existence 

 of boracic acid not merely in boraclte, datolite, tourmaline, and 

 schorl, in which it had been previously discovered, but likewise 

 in two other mineral species, axinite and colophonite. 



In this year too appeared his announcement of the discovery 

 of iodine, in the mineral spring of Bennington, in our immediate 

 neighbourhood. * Not long before Vogel, Liehig, and Angelini 

 had excited great interest among chemists, mineralogists, and 

 physicians throughout Europe, by the unexpected discovery of 

 iodine in various continental mineral waters. The announce- 

 ment of its presence in the water of Bonnington, — a spring, I 

 may observe, of exceeding interest on account equally of its con- 

 stitution, as of its active properties, — was the first observation 

 of the kind made in Britain ; and it has been followed up, as 

 every one knows, by the detection of the same ingredient in 

 many other springs in England by Dr Dauheny. 



The subsequent year of 1827 was by much the most momen- 

 tous in Dr Turner's career as an author and as a public man. 



In the first place he made public five additional specimens of 

 his experimental skill. The first was a " Chemical Examina- 

 tion of Isopyre,"-f- a new mineral species recently established by 

 Mr Haidinger, which he found to be composed of silica, alu- 

 mina, lime, and peroxide of iron. Another was the analysis of 

 a mineral from the hot spring of Oxahver in Iceland, which Sir 

 David Brewster established as a new species under the name of a 

 Oxahverite, and which proved to be almost identical in compo- 

 sition with a previously known species, Apophyllite, as Sir David 

 had inferred from its external characters and optical properties. J 



" Edin. New Philos. Journal, i. 159, 1826. The experiments on the Bon- 

 nington water were made at my request in Dr Turner's laboratory, hy one of 

 his pupils, my young friend Mr Copland of Blackwood, who found it to con- 

 tain iodine. — Edit, of Phil. Journ. 



t Edin. New Philos. Journal, iii. 26.5. 1827. 



t Edin. Joum. of Science, vL 118. 1827- 



