oio Count de Bournon*s Description of 
acts upon it, very nearly as strongly as it does upon iron in a 
perfectly metallic state. When this substance is immersed in 
nitric acid, no effervescence takes place. By means of a file, or 
merely by the blade of a knife, a black powder may easily be 
obtained from it, without in the least diminishing the lustre of 
the part from which it is taken. If a magnet be brought near 
this powder, it is instantly attracted by it. Those parts of this 
substance which appear to have been exposed for any length of 
time to the contact of the air, are become of a black colour. 
I know no other metallic ore whose exterior characters are 
analogous to those I have just described; and I very much 
regret that the scarcity and the consequent value of this speci- 
men, as well as of that about to be described, prevent their 
being made use of for the purpose of an analysis, the result of 
which it would be so desirable to be acquainted with. If, 
without such analysis, I might be permitted to form an opinion 
respecting this substance, I should be much inclined to consider 
it as a martial pyrites, or sulphuret of iron ; but in which the 
iron, in a metallic state, is combined with a much smaller quan- 
tity of sulphur than in common pyrites ; some small traces 
of the latter, however, may be perceived in this specimen, by 
the side of the metallic substance above described.* 
In this same calcareous spar may also be observed, small 
crystals of a greenish colour, which have hexaedral prisms ; 
they are of very inconsiderable hardness. I believe they belong 
to that particular species of phosphate of lime, which the Ger- 
mans have distinguished by the name of spargelstein . 
* Since the above was written, I gave a few grains of this substance to Mr 0 
Chenevix ; who, from that small quantity, was able to determine that it contained 
nothing but iron and sulphur. 
