238 Biographical Memoir of the laie Dr Turner. 



coloured lights. Of the merits of this production I cannot 

 presume to speak. But it may perhaps be allowed me to say, 

 that the leading facts and principles contained in it have never 

 been controverted, — and to bear my testimony, that Dr Turner 

 sustained his full share in the whole investigation. Nor can 

 I forbear from adding, that had the company who proposed 

 the inquiry attended to the warnings conveyed in this paper, 

 and more expressly in a subsequent report never made public, 

 they would have been saved a considerable part of the enor- 

 mous loss to which their recklessness eventually subjected them. 

 With the heedless spirit of the day they erected vast works be- 

 fore determining the scientific data on which their fate was to 

 depend ; and with an obstinacy worthy of a better cause, they 

 went on with their operations for two years after they might 

 have seen, from the data at last obtained, that they had embark- 

 ed in a ruinous undertaking. 



During the same year Dr Turner produced no fewer than 

 five other papers, principally on the subject of mineral analysis. 

 One was an account of some improvements in the preparation of 

 hydriodate of potash,* a salt which was even then coming greatly 

 into demand in consequence of the discovery made five years be- 

 fore by Co'indet of the virtues of the compounds of iodine in 

 goitre and scrofula. Dr Turner's method, which consists in 

 forming in the usual way a mixture of hydriodate and iodate 

 of potash by means of aqua potassoe, and converting the iodate 

 into hydriodate by a stream of sulphuretted-hydrogen gas, is a 

 very convenient and economical process, which, I believe, is now 

 followed by some manufacturers. Another of his papers pub- 

 lished the same year, was his analysis of two mineral speciesi* 

 newly determined by his friend Mr Haidinger, then resident in 

 Edinburgh. From external characters Mr Haidinger distin- 

 guished the minerals in question as two species of Gypsum-ha- 

 loide, instead of Selenite and Quartz, for Avhich they had been 

 mistaken. His coadjutor's results were equally satisfactory ; 

 for he determined them by analysis to be both hydrated arse- 

 niate of lime. About the same period was also published Dr 



• Edin. Med. and Surg. Journal, xxir. 20. 1825. 

 t Edin. Journal of Science, iii. 306. 1825. 



