(QUANTITATIVE (CLASSIFICATION 
Based on chemical and 
mineral characters, 
with a systematic 
nomenclature. 
By WHITMAN CROSS, 
JOSEPH P. IDDINGS, 
LOUIS V. PIRSSON and 
HENRY S. WASHINGTON; 
wT 
oF [GNEous Rocks 
ONTAINS a critical review of various systems of 
& petrographic classification that have appeared in the 
nineteenth century which forms a historical introduction 
to the new system of quantitative classification and the nomen- 
clature proposed by MEssrRSs. Cross, IDDINGS, PIRSSON, and 
WASHINGTON. The authors also propose a simplified classi- 
fication and nomenclature of igneous rocks for use in the 
field and for those who are not petrographers. This is based 
¢ | wholly on megascopic rock characters, and is virtually a res- 
toration of the earliest system in vogue with the founders of 
the science. Methods of calculating mineral composition from 
the chemical composition of rocks, and the reverse, with tables 
to aid the operation, are set forth at length. There is alsoa 
glossary of new terms employed by the authors. 
8vo cloth, ze, $1.75; postpaid, $1.89. 
ghar esta of Sys- 
tomate on iy inthe 
Nine th Century,” by 
Wuirman Cross. 
TELE UNIVERSITY OF  CHICAGY PRESS 
ICAGO, ILLINOIS 
Methods in Plant Histology 
By CHARLES J. CHAMBERLAIN, A.M., Pu_D., Instructor in Botany in the University of Chicago 
A CONSTANT HELP to Teachers and Students of Botany 
CONTAINS DIRECTIONS FOR COLLECTING AND PREPARING 
PLANT MATERIAL FOR MICROSCOPIC INVESTIGATION 
esult of ral ye aes classes in residence 
rsity “Extens 2 
nly ry vn stude nt Peale has the assist 
| 1s based u up 
be published on this subject. It is the r 
at t i Chicago, and with Univ 
ett 
versity. It aims, therefore, to meet the oeciesnatias not 
ance of an instructor in a fully equipped laboratory, but ep so othe student who must work by himself 
and with limit apparatus. Free-hand sectioni ng, t method, lodion method, 
and € glycerine method, are treated in considerable detitl In later chapters specific direc- 
tions are given for aking such preparations are needed by those who wish to study the 
plant kingdom fro Igze up to the Hanierieg plan ae Special attention is paid to the stain- 
ing of karyokinetic figures, because the student who masters this problem will find little difficulty 
the 
ifferen ntiating si structures. Formulas are given for the reagents commonly used in 
histological cane 7, 
ra A , 8vo, illustrated, cloth, (ze?) $1.50; postpaid $1.59 
For sale by dealers or by the publishers 
The University of Chicago Press, Chicago, Illinois 
