86 
POPULAR SCIENCE REVIEW. 
saw in nature ; but with my prepossessions and habits, both as an ento- 
mologist and a housekeeper, I was contentedly interested to see the work 
go on.” 
Changes in the Position of Grains of Chlorophyll by Sun-light. — M. Borodin 
has found that this takes place in the higher cryptogamia and in the phane- 
rogamia both aquatic and terrestrial [see Ann. des Sciences naturelles , sec. 
5 to 12]. Lemna, CeratophyUum and Collitriche are among the aquatic 
plants in which the phenomenon has been observed, and Stellaria media 
among terrestrial. Lemna trisulca is one of the best plants for these obser- 
vations. Under diffuse day-light the grains of chlorophyll are distributed 
over the cell-walls parallel to the surface of the leaf or frond. Under the 
direct light of the sun they are rapidly (within 15 minutes or less) trans- 
ported to the lateral walls. There they are at first uniformly distributed. 
But upon longer insolation, say for three-quarters of an hour, they became 
grouped in clusters. In darkness the chlorophyll is likewise upon the lateral 
walls. Thus absence of light produces essentially the same effect as direct 
sunshine, but less strikingly. Whether these changes are passive and caused 
by movements of the colourless protoplasm, as Sachs supposes, or active, is 
not made out. But the movements, according to Borodin, are in response 
only to the more refrangible rays. 
J Decomposition of Carbonic Add by Leaves. — M. Deherain has published 
an important paper on this subject and synopsis of the amount of water 
which evaporates. Among some of his more important conclusions are the 
following: — (1.) That the transpiration of water continued indefinitely, 
and quite constantly, in a saturated atmosphere. (2.) This evaporation, 
copious in light and almost null in darkness, is determined by the light, and 
not by the heat of the sun. (3.) It is much greater from young leaves 
than from older ones. (4.) And is mainly caused by the luminous rays 
(yellow and red). (5.) The difference in this respect is manifest even when 
the less refrangible and more refrangible rays are brought to an equal lumi- 
nous intensity. (6.) The evaporation of water is much more copious from 
the upper than from the lower face of the leaf. 
CHEMISTRY. 
Action of Gun Cotton on Camphor. — Professor C. A. Seeley recently 
called the attention of the Lyceum of New York to a property of gun 
cotton which he considered new, or at least unrecorded. It was well known 
that gun cotton was soluble to a very considerable extent in alcohol which 
held gum camphor in solution. A knowledge of this fact had been made 
use of in the arts, for the manufacture of an artificial ivory, which was 
reported to be fully equal, if not superior, to the genuine article. In making 
this substance, the gun cotton is ground up with the gum camphor, by 
means of water, into a pulp, and then pressed into a solid mass, whilst 
being heated to a temperature of about 300° F. Taking this fact into con- 
sideration, he had thought of ascertaining what would be the effect of 
exposing gun cotton to the action of the vapour of gum camphor. There- 
fore a small quantity was thus exposed in a glass tube : the camphor being 
