46 
terial aid to the construction of his right- 
handed and left-handed molecules! It is 
strange that more use has not been made of 
the ordinary stereoscope for purposes of 
scientific illustration ; instead of having ex- 
pensive models of the forms of higher 
mathematics, every purpose would be sub- 
served if a set of stereoscopic views of them 
were provided. With this new and more 
simple device there is every reason to hope 
that representation in the solid, requiring 
merely that a person should take his red 
and green glasses out of his _ pocket, 
will become nearly as much a matter of 
course as plain, or rather plane, diagrams 
are now. 
Another field for the application of this 
principle is in illustrations thrown on the 
screen for large audiences. There would 
be no difficulty whatever in projecting one 
picture of a stereoscopic pair through a red 
glass on to the screen, and the other through 
a green glass, and providing the onlookers 
with the corresponding spectacles; this, in 
fact, is the special form of the process which 
is already in use in other countries. For 
this form, as well as that on a card for in- 
dividual use, stereoscopic pictures already 
made need only to be reproduced in the 
proper colors to answer the requirements of 
this new method. 
As regards the painter of pictures in the 
artistic sense, it is perhaps prophetic that 
he has already furnished his paintings 
strong purple shadows ; he has only to in- 
tensify the greens on the other side of his 
trunks of trees, and to provide the neces- 
sary green and purple glasses for his critics, 
in order to show them a picture of reality, 
such as he has before only dreamed of pro- 
ducing. 
The process ought, therefore, to have an 
important future. The present publisher in 
the Redheffer Art Publishing Co., Balti- 
more Building, Chicago. 
C. Lapp FRANKLIN. 
SCLENCE. 
[N. S. Vor. X: No. 237. 
THE INTERNATIONAL CATALOGUE OF SCI- 
ENTIFIC LITERATURE. 
BOTANY. 
Ir is manifestly quite impossible to-day 
to make a satisfactory schedule of the clas- 
sification of botanical books and papers for 
use in libraries, since, to be satisfactory to 
the botanists, it should represent the pres- 
ent development of the science, while, on 
the other hand, such a representation would 
be far beyond the technical botanical knowl- 
edge of the librarians. It is the misfortune 
of Science that much of its administration 
must be entrusted to persons who have, at 
the best, only a general knowledge of the 
subject, and this very often representing an 
old phase of the science, long since aban- 
doned in the laboratory and lecture-room. 
It is, perhaps, impossible to have it other- 
wise, at least for a long time to come; we 
cannot require librarians to know as much 
in regard to the progress of Science as the 
workers themselves. It is inevitable, there- 
fore, that any scheme of the classification 
of botanical books which ean be used by 
librarians must fall considerably short of 
representing the present condition of the 
science. On the other hand, as revisions of 
library schemes are made from time to 
time, it is desirable that the classification 
should be brought forward somewhat nearer 
the present coudition of Science, as far, at 
least, as can be done with safety, since no 
library, by its inertia, should become, to a 
marked degree, the conservator of aban- 
doned scientific views. 
The International Catalogue Committee 
apparently have kept in mind something 
like the foregoing, and have wrought out a 
scheme which will no doubt be workable by 
librarians and those whose knowledge of 
Botany is general rather than specific. 
Probably few, if any, objections will be 
brought against it by the librarians and 
general students of plants, at least in so far 
as the general plan is concerned. We may, 
