J. Lawrence Smith on Emery. yo 
or some other hydrate of alumina; but after the most caréefyl and 
repeated examinations, this has been decided in the negative. 
Hydrargillite—Hydrargillite is rarely met with. I have one 
Specimen with this mineral forming the external coating of a 
erystal of corundum, and also a hexagonal prism of the same min- 
eral. It was not analyzed, but its physical properties and its re- 
actions under the blowpipe served to prove its identity with this 
eet ‘The specimen in my possession comes from Gumuch- 
dagh. 
_ Diaspore.—This mineral up to the present time has not occu- 
pied a very important position in mineralogy, and has been found 
only in two or three localities. In the course of this article, I 
hope to show that it plays a somewhat important part in the em- 
ery and corundum formations. Before my attention was drawn 
To the localities of diaspore already known, I have toadd those 
a Gumuch-dagh and Manser in Asia Minor, and the islands of 
almost every corundum locality. I have already found it on 
crystals of corundum from China. 
i examining the emery formations, one of the first things that 
Struck my attention was the existence of diaspore and corundum 
together, then observed for the first time. The same year, M 
Marignac discovered it in the limestone of St. Gothard, along 
Hy 
a: 
