FOREIGN CORRESPONDENCE., 
121 
lime is dissolved in its turn, when a residue, consisting of very fine 
non-crystalline particles, and amounting to about two per cent, of the 
weight of limestone employed in the experiment, is found to remain 
undissolved. These particles consist of arsenlferous iron-pi/rites. A 
fact that should be noted here is, that M. Daubree formerly dis- 
covered arsenic in the limestone of the coal-formation at Ville, and 
found that it was contained in the rock as crystallized particles 
of Mikspikel (Fe As-f- Fe S^), the small crystals of which were perfectly 
recognizable. 
As regards the environs of Lobsann, it is not only in the beds 
of lignite and bituminous limestone that arsenic is found to be pre- 
sent. Near this locality there exist some masses of iron-ore, which 
are very remarkable as regards their geological position. One of them, 
at Kuhbriick, about two-and-half miles from Lobsann, furnished the 
blast-furnaces with an hydrated oxide of iron which contained so much 
arsenic, that it was found useless to smelt this ore any longer. These 
masses of ii'on-ore " have been developed," says M. Daubree, " in a 
series of faults (failles) with which the formation of the bitumen in 
the tertiary formation is connected, as I have shown in another 
memoir, so that in these deposits of such different natures, but con- 
temporaneous, the arsenic appears to have been derived from the same 
source." 
We have called attention more than once in the Geologist of last 
yeai', to the beautiful researches of M. Daubree on Metamorphism, on 
the artificial formation of many minerals, &c. ; and Professor Bunsen, 
at the last Reunion of Natm-alists, at Carlsruhe, declared that for five- 
aud-twenty years no work of so much importance for geology had 
been published, as M. Daubree's researches on Metamorphism, &c. 
We wish, therefore, that it had fallen into the plan of the late Pre- 
sident of the Geological Society of London to have noticed the labours 
of M. Daubree, in his yeai-ly account of geological investigations in all 
countries dui-ing the previous year (1857), and that he had thus added 
the weight of his testimony to that of the many eminent foreigners 
who have expressed their high opinion of M. Daubree's labours, as 
the opinions and writings of English savans of so high a standing 
have a great influence on the Continent.* 
As regards the very interesting note appended by the editor of the 
Geologist to my last article, I must observe that I was aware that 
the noises of guns could be heard at considerable distances, and 
* It must be remembered that the address which Dr. Phipson alludes to was 
delivered betVire the Geological Society in Feliruary of last year, and, if we re- 
member rightly, very shortly, indeed, after the most interesting of M. Daubree's 
researches were first puljlished. It is somewhat rmusual to notice " sins of 
omission " in tb.e president of a society ; but, as the remarks are evidently kindly 
intended, we publish them, in order that it may be fully known on the Continent 
that M. Danl iree's researches are not by any means slighted by English savans. 
ladeeii, they were noticed with muoh emphasis by the present President of the 
Geological Society, Professor Phillips, in the anniversary addi-ess delivered a few 
days since. 
