Mineralogy and Geology. A27 
The work next in importance, more especially in its bearing on the 
crystallization of Minerals, is the “ Elementary Introduction to Miner- 
alogy,” by Brooke & Miller. It stands preéminent for its original 
measurements, and its thorough revision of the angles of Crystals, and 
will remain a permanent source of information on these points 
In the preparation of the present edition, the author takes pleasure 
in making special acknowledgements to the work of Bischof, for facts 
and principles relating to the Chemistry of the alteration of Minerals ; 
to Rammelsberg’s Supplement to his Chemical Mineralogy, a wor 
whose earlier parts contributed largely to the preceding edition of this 
Treatise ; to Kenngott’s and Kokscharov’s publications; and to the 
critical observations in the ‘“ grrr gia: of G. Rose. Frequent 
use has also been made of the work of Brooke & Miller, in the crys- 
tallography of the species, from ‘hich the, angles and planes of erys- 
tals have often been cited. The various Scientific Periodicals of Rus- 
sia, Germany, Italy, France and Britain, some of them down to June 
last, have ‘il searched for their facts, and every effort has been made 
to post the work up to the day of publication. 
American Mineralogy owes much to the pont revision it has re- 
ceived at the hands of Messrs. Smith & Brush ; the author would 
express his special personal obligations to are ‘of these Chemists. 
From ne r. F. A. Genth, of ie ee he has source generous aid 
both in suggestions and. sults of researches. . T. S. Hunt has 
kindly contributed seve eal new analyses throwing alice light on the 
minerals of Canada; and valuable observations and analyses have 
been received from J. D. Whitney and Professor Booth. Many a 
various have been the favors, in the way of new facts, opinions and 
recent discoveries, which the author owes to Mr. Louis Semann of 
Paris. He i P 
ari is also largely indebted to Robert P. Greg, Jr., of Man- 
chester, England, for information respecting the Mineralogy of Great 
Britain, liberally tarnished from * work . by him and«W. G. Lettsom, 
now in the pre 
S. 
In the preparation : this a. the subject of Crystallography has 
been revised and simplified. A system of notation for the figures of 
crystals, both brief and simple, a been adopted ; and many new and 
original figures have been introduce he homeomorphous relations 
of mineral species have n ke with ne epeaiieg = ey 
order to arrive at their true fundamental forms, and bearing 
tra 
of the subject on their composition and classification. “The Table of 
_ atomic weights has been corrected according to the most recent results, 
pond with it. The subject of pr gre is treated at some saane 
and along with the descriptions of the Apes raph is 
to the altered forms which each presen _ changes, etiod 
with the renee of the 2 eab Be gt G8 the large additions 
throughout, render the Treatise more properly a new work, than a re- 
vee edition. 
5. Lanthanite.—Prof. J. Lawrence SmitH, as an addition to his 
account of this species, on page 378, mentions that the specific gravity 
is 2848, a little higher than the determination of W. P. Blake. Prof. 
Smith freed the mineral from air by boiling it and then using the air- 
