On the Metallic Salls. 353 
which fell in the environs of Langres is formed in the proportion 
of ten grammes, as follows: 
Silex th ~. 9-39 pr, 
~  Oxidated iron gui. int LO 
Magnesia .. -- 3°20 
Metallic chrome .. 20 
9-89 
Or of 100 parts: 
Silex MA os 30° DO) BT 
Oxidated iron eae LOD 
; Magnesia .. 2. o2°00 
Chrome .. ny 2-00 
98:90 
Remarks. 
We remark here: Ist, that the Langres stone contains neither 
sulphur nor nickel, and that the iron in it is entirely oxidated ; 
whereas all the other aérolites contain those two substances, and 
the iron has always been in the metallic state, at least for the 
most part. 2dly, That a part of the silex contained in the stone 
is only in the state of mixture in the sandy form, and that an- 
other more abundant portion than the first is entirely combined 
with the magnesia, and probably with the iron, since it is dis- 
solved at the same time with those two bodies in the sulphuric 
acid. 3dly, That there is in the present stone twice as much 
magnesia as in those which have been hitherto analysed: per- 
haps its softness was owing to this cause. 4thly, Lastly, the 
chrome is found in it in the metallic state, which announces that 
it must have resisted the oxidating action which burnt the iron. 
The quantity of this metal is also more considerable than usual. 
It is probable, that if the sulphur has existed primitively in 
this stone, it must have been dissipated at the moment when the 
iron was fused. 
The absence of nickel from. this stone found at Langres is 
the more remarkable, as it has been constantly found in all other 
aérolites, 
nay" So: AES aA ID 
LXXI. On the Metallic Salts, By G. 8, 
To Mr. Tilloch. 
Sir, — In my last I stated, that Mr. H. asserted the metallic 
salts to be super-salts with excess of oxide; 1 made the same 
statement in a former paper, and combated it without any charge 
Vol. 47. No. 217. May 1816, Z of 
