Geology and Natural History. 507 
ion volume. In the crystallography the author wisely chooses 
the system of Miller for full development, while the notations of 
Weiss, Naumann and Lévy are also explained. The statements 
system, are given with admirable fullness and clearness, and the 
figures are also numerous and excellent, The author states that 
he inten ntionally omits the subject of practical calculation, but had 
it been possible to abridge a little at other points so as to have 
made room for a few pages on this part of the subject the useful- 
ness of the book would have been much increased. The pes 
subject of optical mineralogy is i ed with unusual suce 
and this also is true of the other topics under physical a s alo 
E, 
lan ccvastastinated. March 18). Sadaateed twins of Zircon 
pare lately been obser ved by the writer ine 
it h 
t best questionable. 
: enhorst’s ) epi men- Flora von Deutschland, Oester- 
reich und der Schweiz; vol. I, parts 1 and 2; by Dr. G. Wis ER. 
“we 
r > 
7 others, and from this list of names it will be seen that the scope 
é of the work is considerably greater than that of the first edition, 
; which was written by Ra i nhorst alone. The marine alge, for 
instance, which were before omitted, are to be described b 
auck, whose residence at Triest has given him an opportunity to 
explore the interesting coast of the northern Adriatic he two 
parts already published include the Schizomycetes, pe sted 
cetes, Entomophthoree we Aipiaiiodg oe! by Winter. The whole 
account, including about Fan $ with an introduction 
the m atte ashe rather minute 
directions about collecting and mo Ra- 
enhorst’s “‘ Flora Europea Alga gS ue  Dulcis,” the descrip- 
tion of the ao of the different gre is precede woo 
* See Mey S. G., Ges., — 11,352; Stapff, 1. c., xxx, 133, xxxi, 405; Hussak, 
Min. Petr. Mitth, i, 277, 1878 
