374 P>°f- Berzelius on Lilhion and Selenium. [May, 



Prof. Berzelius then enters into a description of the selenium. 

 He informs us that in a manufacture of sulphuric acid, be- 

 longing to M. Gahn and himself, sulphur is burned which is 

 procured from the mine of Fahlun, and that it deposits on the 

 floor of the great leaden chamber a reddish mass, which is prin- 

 cipally composed of sulphur. From the odour which this red 

 mass gave out when it was burned, it was thought to be tellu- 

 rium, but no tellurium could be obtained from it; and this induced 

 Prof. Berzelius to examine it with more minuteness, when he 

 discovered the selenium. With respect to the odour of this 

 substance, it is stated, that if it sublimed in the air without taking 

 fire, it is evaporated in the form of a red smoke, which has no 

 particular smell. But if the flame of a candle be directed upon 

 it, or it be heated by a blow-pipe, it tinges the flame of an azure 

 blue, and exhales so powerful an odour of the radish, that if -^ 

 of a grain be evaporated,, it is sufficient to fill the air of a large 

 apartment. Klaproth has stated that this odour is given out by 

 tellurium ; but Berzelius remarks that neither purified tellurium, 

 nor its oxide, nor its combinations with the metals, produces this 

 odour. In order to produce this effect it was necessary to enclose 

 a small portion of tellurium in a little ball of thin glass, and to 

 heat it with the blow-pipe, until the tellurium, being converted 

 into gas, penetrated the ball through a small orifice ; in this case 

 the smell was precisely the same with that of the new substance. 

 If a little muriatic acid be poured into the solution of a sele- 

 nate, and a bit of zinc be put into it, selenium is precipitated in 

 the metallic state ; at first the zinc appears as if it were covered 

 with a pellicle of copper, afterwards the selenium is deposited in 

 flakes of the colour of cinnabar. If instead of muriatic acid we 

 employ sulphuric acid, the precipitate is made with more diffi- 

 culty, assumes a grey colour, and contains sulphuret of selenium. 

 If a stream of sulphuretted hydrogen gas be passed through a 

 solution of selenic acid, the selenium is precipitated of an orange 

 colour : it becomes red when dried, exposed to heat it melts, 

 sublimes, and yields an orange-coloured transparent mass. It is 

 stated that, although the selenium is extracted from the pyrites 

 which is used to procure sulphur for the manufacture of sul- 

 phuric acid, still the acid does not Contain the selenium, because 

 the sulphurous acid has the property of reducing the selenic acid 

 to the metallic state. 



With respect to the lithion, or lithina, we may add that the 

 discovery of M. Arfredson has been confirmed by Sir H. Davy, 

 who has procured the new alkali, and has found its properties to 

 agree with those stated by the Swedish chemist. Sir Humphry 

 has also succeeded in reducing it to the metallic state ; lithium, 

 as it may be called, bears a strong general resemblance to the 

 other alkaline metals, and especially to sodium, to which it seems 

 to be the most nearly allied. 



We learn by a letter from M. Gillet de Laumont, inserted in 



