19 
and Sulphuretted Prussiates. 
pliuret of cyanogen with hydrogen, is composed ' also of eqUal 
volumes of azotje, of hydrogen, of carbon, and of sulphur. M. 
Berzelius admits, that the phenomena presented by the eyanu- 
rets and the sulpho-cyanurets, can only be explained by a theory 
analogous to that which Sir Humphry Davy and M. Gay Lus- 
sac have applied to the muriates, with which M. Berzelius finds 
that the sulpho-cyanurets have a striking analogy. This ana- 
logy allows us to presume, also, on an analogy between chlo- 
rine or the oxymuriatic gas and the sulphuret of cyanogen. M. 
Berzelius has attenipted to obtain this last substance in an insu- 
lated state, for the purpose of studying its properties ; but he 
has hitherto tried it in vain. 
Selenium gives with the cyanuret of iron and of potassium 
phenomena analogous to those produced by sulphur. The se- 
lenio-cyanuret of potassium resembles perfectly the sulpho-cya- 
nuret ; but if we mix it with any acid, the Selenium is imme- 
diately precipitated in red flowers. 
Tellurium allows itself to mix with the double cyanuret of 
iron and potassium, if they are melted together ; but water se- 
parates them; the cyanuret dissolves without alteration, and the 
Tellurium remains in the form of a metallic powder. 
S. Account q/* M. MitscherlicK s Experiments on the Forms of 
artificially crystallised Salts. 
M. Mitscherlich, a young chemist from Berlin, has been 
much occupied in determining the form of artificially crystal- 
lised salts. In the course of this inquiry, he has arrived at 
many results of very high importance respecting the relation 
which exists between the composition and the form of these 
crystals. Having studied during the last year under M. Ber- 
zelius, he has repeated before him a great number of his experi- 
ments, which were found to be perfectly exact. M. Mitscher- 
lich has discovered that several substances, simple as well as com- 
pound, may replace one another in compound bodies, without 
any change of form taking place in the latter, provided that the 
other constituent principles remain the same, and in the same 
proportions. He has found for example, that Phosphorus and 
Arsenic replace one another in such a manner, that the Phos- 
E ^ 
