424 Scientific Intelligence. 
Hausmann next compares the specific gravity of certain slags in the 
stony and glassy states. He then proceeds to apply the subject to Ge- 
ology, comparing the furnace products with volcanic ejections and other 
igneous rocks, e minerals of slags, pyroxene, chrysolite, feldspar, 
humboldtilite, are observed to characterise the Vesuvian lavas. 
distinguishes between the volcanic, vulcanoidie and Plutonic rocks, the 
ast never running into glassy forms and abounding in silica ; the second 
kind an intermediate class between the volcanic and the Plutonic. 
ourth edition, rewritten, rearranged and enlarged. 2 vols., an 
534 pp. 8vo. ork and London: Published by George P. Put- 
nam & Co. .—As a notice of the new edition of this work we eile 
science. ‘ ey) 
A classification on chemical principles was however proposed in a 
latter part of the volume, in which the Berzelian method was couple F 
with crystallography, in a manner calculated to display the relations © 
. ibit the 
various cases of isomorphism and pleomorphism among Minerals. 
; ter pre- 
entitled to 
hether 
