[ 536 ] 



LXXVI. Chemical Notices from Foreign Journals, 

 %E. Atkinson, Ph.D., F.C.S. 



[Continued from vol. xxv. p. 545.] 



BOTTGER*, who has investigated the deposit in the lead cham- 

 bers of numerous sulphuric acid works, states that he has as 

 yet only observed the occurrence of thallium in two cases. It does 

 not appear always to accompany selenium : a very rich selenife- 

 rous deposit from Zwickau contained no thallium; and in a 

 thalliferous deposit from a manufactory at Aix-la-Chapelle no 

 trace of selenium could be detected. Bottger extracted the thal- 

 lium from a deposit in sulphuric acid chambers at Oker in the 

 Hartz, in the following manner. The reddish crumbly deposit 

 was boiled with six times its quantity of distilled water, and 

 powdered carbonate of soda added until the disengagement of gas 

 had ceased, and the mixture had assumed an alkaline reaction. 

 The boiling was continued with continual stirring until the ori- 

 ginal red colour of the deposit was changed into black. The 

 whole was then filtered and the residue washed on the filter; to 

 the united filtrate and washings a small quantity of cyanide of 

 potassium was added, the liquid again filtered, and sulphuretted 

 hydrogen passed through the filtrate so long as black sulphide 

 of thallium continued to be precipitated. This was washed by 

 decantation and collected on a filter. The black deposit result- 

 ing from the treatment with carbonate of soda still contained 

 thallium ; it was accordingly boiled with moderately strong solu- 

 tion of oxalic acid so long as the spectroscopic reaction of thallium 

 could be obtained. The filtered liquid was then made alkaline 

 by carbonate of soda, a quantity of cyanide of potassium added, 

 the whole boiled, filtered, and the filtrate precipitated by sul- 

 phuretted hydrogen. 



This precipitate consisted of sulphide of thallium containing 

 sulphide of mercury; it was treated with pure nitric acid (of 

 spec. grav. 1'20), by which sulphide of thallium alone was dis- 

 solved out. This nitric acid solution was mixed with concentrated 

 sulphuric acid, the whole evaporated to dryness, dissolved in 

 boiling water, the liquid concentrated, and the thallium precipi- 

 tated by zinc. 



In a subsequent paper f Bottger describes the extraction of 

 thallium from a deposit which had formed behind a pyrites fur- 

 nace in a sulphuric acid works in which Belgian pyrites was 

 used. This had a reddish colour, and consisted of sulphates of 

 zinc, sesquioxide of iron and thallium mixed with charcoal and 

 sand. 



This residue was very finely powdered, and boiled with four 



* Liebig's Annalen } Mny 1863. f Ibid. June 1863. 



