404 Miscellanies. 
at least its discovery has been alleged, and that in a doubtful manner, 
in but three or four localities. This aerolite resembles, on the contrary, 
in a remarkable manner, some of the slags of the furnace. Examined 
with a strong magnifier, two distinct minerals are recognized: one im- 
perfectly lamellar, presents in some parts bands analogous to those 
which characterize the hemitropic masses of albite or labradorite : the 
other, of a vitreous fracture, might be taken for quartz, if we did not 
ow from numerous observations, that this mineral is not found in true 
voleanic rocks, nor in those of meteoric origin. Besides these two min- 
erals, the eye detects small black glassy globules, analogous to perlite. 
These are evidently the product of fusion, and their gray, interior, which 
is like the general texture of the stone, has not been altered by the heat. 
Finally, there are to be detected small shining black plates, which are 
particularly collected about the veins which traverse the stone. ‘These 
small plates resemble the scales of | graphite which exist in some varie- 
ties of gneiss. The gravity of the stone is 3.56: that of the grains of 
metallic iron, extracted by the magnet, is 6.48 
_ Before the blowpipe, a fragment is Spuinedntaly reduced to a black 
hollow scoria, like that of the exterior crust of the stone. This proves 
that the crust is the result of the fusion of the exterior parts, which are 
oxidized to a very high degree by their contact, when at an elevated 
temperature, with the atmosphere. 
M. Dufrenoy gives the following as the result of three analyses which 
he made. 
Silica, : , 38.13 
Magnesia, : : ‘ ‘ : : 17.67 
Protoxide of iron, . ; ‘ : ; ~ 29.44 © 
Protoxide of Eth : . ‘ . a trace. 
Alumina, - < y $ ; ») 782 
ime, ‘ é IR F ‘ 14 
Metallic iron, d j . ; é oh 
Nickel, ; 1.55 
Sulphur, ‘ j i 39 
«#~ Potassa, 3 ‘ ‘ 27 
Soda, 86--99.97 
_ Ot grouping together the shuhaasta whic are eon binisd= 
iron and nickel, 9. 
take : § Fg eae 
pea re iduble 3 in alate ; -  B162 & 
Matter insoluble in acids, and not related to ay 
—— - 38. 17.99: 71 
haa | Phhotta, Iuly 2 22, 1841, No. ahi 
* | 
