378 Scientific Intelligence — Mineralogy. 



many geological phenomena. Two facts, which seem to confirm this 

 supposition, are, first, the existence of the chromate of iron in masses, 

 and not in veins ; and, secondly, the pale colour of the serpentine 

 associated with the chromate. One small specimen that I have, con- 

 sists of a white rock, composed principally of carbonate of magnesia, 

 ill which small specks of chromate of iron are visible. It is possible 

 that this carbonate is the result of the decomposition of the serpentine 

 at the surface, by the action of water containing carbonic acid. It 

 is only at this locality that I found crystals of the chromate, octahe- 

 dral, but very small. 



This discovery is of great importance to the arts, and to the 

 Turkish government, which proposes exploring the mine. 



In quitting the locality of chrome, and going north-east, I tra- 

 versed, in several places, the serpentine containing veins of cai'bonate 

 of magnesia, quite pure ; and this occurs until we arrive at the 

 plains of Eskihi-sher. It is from different parts of this plain that 

 comes the meerschaum most esteemed in the arts. Its geological 

 position is very different from what I had expected. The plain in 

 which it is found is a deposit of drift ; a valley filled up with the 

 debris of the neighbouring mountains, consolidated by lime in which 

 I found no fossils. 



The meerschaum is found in this drift in masses more or less 

 rounded ; the other pebbles are fragments of magnesian and horn- 

 blende rocks. 



I have examined, with care, the neighbouring mountains which 

 surround the plain, and have found that the rocks are of the same 

 nature as the pebbles in the plain, except those of the meerschaum ; 

 but, on the other hand, I found carbonate of magnesia in the moun- 

 tains, which is not to be found in the plains. And this makes me sup- 

 pose that the meerschaum owes its origin to the cai'bonate of mag- 

 nesia of the mountains, decomposed after its separation, by water 

 containing silica. 



If this supposition be true, we should naturally find meerschaum 

 which, not being completely altered, contains the carbonate of mag- 

 nesia. A chemical examination of several specimens has served to 

 establish this fact. I have the honour to send you a specimen taken 

 at the depth of ten feet ; and if you desire to make the experiment 

 yourself, put a small piece of the specimen, well cleaned, in hydro- 

 chloric acid. You will have immediately an effervescence which 

 will continue for some time ; the piece will not change its form, it 

 only absorbs the acid ; the solution will be found to contain chloride 

 of magnesium nearly pure. Another proof that the meerschaum 

 probably owes its origin to the carbonate of magnesia, is, that I have 

 found attached to the meerschaum, serpentine, similar to that found 

 in contact with the carbonate of magnesia of the mountains. 



The meerschaum of Eskihi-sher differs completely from several 

 other specimens that I have seen coming from the localities, and 

 which exist in the fissures of rocks. It is certain that the quality of 



