202 Miscellaneous Intelligence. 



combination produced these effects. 7.094 parts of ammoniated 

 iron were heated in a tube, and hydrogen gas passed over them j 

 the gas was dried before coming into contact with the metal, and 

 again afterwards by passing through a tube containing chloride 

 of calcium, and carefully weighed ; the iron was reduced to 6. 585 

 parts in a pure state, so that it had lost 0.509, and the chloride 

 of calcium tube had increased in weight only 0.05. Oxygen, 

 therefore, could not have made more than ^i^th of the matter which 

 had been fixed in the iron. Other experiments gave a smaller 

 quantity of water. The water through which the gas passed, 

 after leaving the iron and drying tube, rendered syrup of violets 

 green, and contained ammonia. Hence there is reason to believe 

 that nitrogen is the substance absorbed by the iron. 



Ammoniated iron, dissolved in dilute sulphuric acid, gave hydro- 

 gen gas mingled with nitrogen, the latter being occasionally as 

 much as 6 per cent, of the whole quantity. All the specimens of 

 iron, which had increased in weight, gave nitrogen gas when dis- 

 solved in acids. The volume of mixed gases evolved is less than 

 the volume of pure hydrogen produced by an equal weight of pure 

 iron, in consequence of the formation of a little ammonia, which 

 may be found by evaporating the acid liquor and mixing quick 

 lime with it ; much ammonia is set free. 



The substance absorbed by the iron cannot be either hydrogen 

 or ammonical gas ; for in the first case the volume of the gas would 

 be greater than with pure iron, and in the second equal *, whilst 

 on experiment it has been found less. Nor does it appear to be 

 carbon. 



Copper is more altered than iron in these kind of experiments ; 

 its specific gravity is frequently lowered ^, being 5.5. It becomes 

 scaly, porous, and coloured variously, grey, yellow, green, orange, 

 red, purple, &c. ; it always has a nacreous crystalline aspect: but 

 it retains a very little extraneous matter. It is, therefore, sup- 

 posed that the copper combines with a considerable quantity of 

 azote; but immediately gives off this substance again, for M* 

 Despretz thinks the experiments fully establish the fact that the 

 alteration in the properties of the metals is due to a durable or 

 a momentary combination of them with nitrogen. 



No conclusion is drawn respecting the nature of ammonia from 

 these experiments, but further results are promised. — Ann. de 

 Chimie^ xlii. 122. 



6. Fluid in the Cavities of Rock Salt. — Dr. Nicol has examined 

 certain samples of rock salt, which being clear, colourless, and 

 transparent, exhil)ited small cavities in innumerable quantities^ 

 some of which contained a fluid, and others fluid with a bubble of 

 air. Upon examining the fluid, it was found to differ from satu- 



* Not equal ; ^V*!^ ^^ss, for instance, if only /gths were iron and the rest the 

 peciiliar substance. — Ed. 



