586 Dr, Schafhaeutl on the Different Species of 



35 grains of this steel dissolved in hydro-chloric acid of 

 sp. gr. = 1*104, deposited on the vault of the retort, soon 

 after the acid began to act upon the iron, a dark ring of car- 

 bonaceous matter twice the diameter of the space occupied 

 by the steel filings at the bottom of the retort. The inside of 

 this ring was gradually filled up by the black residuum, 

 whilst at the same time it collected in rays around the filings 

 at the bottom of the retort, which filings in the same ratio 

 disappeared, till the space formerly occupied by them was 

 filled up entirely by the black powder, gradually increasing 

 towards the centre, each grain of this black powder retaining 

 the form of the particle of steel filing from which it had its 

 origin. The action of the acid and the evolution of gas had 

 not ceased in three weeks. The residuum, of a dark brown 

 greenish colour, was equal to 1*995 grains. Heated in a pla- 

 tinum crucible, a single bright spark appeared towards the 

 centre, which immediately disappeared. Long after this the 

 mass ignited within the crucible, and had increased in weight 

 = 0*959. After being treated by hydrochloric acid, 0*381 

 of silica remained, contaminated with a little iron. The 

 greatest quantity of arsenic was found to be contained in the 

 acid from the retort. 



Arsenic, sulphur, silicon, and azote are constituent parts 

 of all the best English steel which I have analysed, made 

 from the Dannemora iron, called Hoop L. and double 

 Bullet. Their relative proportions in all specimens are 

 nearly the same. In some specimens of very hard steel 

 I found the carbon increased to 1*69 per cent. It is 

 scarcely necessary to add, that the arsenic, antimony, and tin 

 were precipitated together by a current of sulphuretted hy- 

 drogen, and sometimes by means of hydro-sulphuret of am- 

 monia. The precipitate was divided into two equal parts; 

 one part dissolved in aqua regia, the diluted solution mixed 

 with tartaric acid and the quantity of sulphuric acid ascer- 

 tained in the usual way. The other portion of the precipi- 

 tate obtained by sulphuretted hydrogen was heated carefully 

 in a glass capsule in a current of dry hydrogen, till the arse- 

 nic was driven off. The antimony and tin were of course 

 left behind. I endeavoured to separate both these, as pro- 

 posed by Gay Lussac, by dissolving the residuum in aqua re- 

 gia, and precipitating one half of the solution by means of 

 metallic zinc ; the other by metallic tin, which only separates 

 the antimony. But to gain an exact result, a larger quantity 

 of the material for analysis is necessary than can be conve- 

 niently obtained by analysing iron. 



If a current of sulphuretted hydrogen is driven through an 



