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BOSTON JOURNAL OF CHEMISTRY. 
Volume XXV. 
BOSTON^, MARCH, 1891. 
ISTUMBEE 3. 
CONTENTS. 
MILIAR Science. — Scientific Recreations . 33 
udies in Plant Biology 33 
n Intimate Enemy 34 
monitions, Coincidences, and Supersti- 
tions 35 
ints for Experimenters 36 
ientiflc Brevities 36 
HE Out-Door World.— The Joy of It . . 37 
An Interesting Letter from an English 
Schoolboy 37 
The Agassiz Bulletin 37 
Personal Observations by Chapter 604, A. 
' A., Fredonia, N. Y 37 
Introduction to the Study of Mosses — 
Prof. Leo Lesquereux 38 
itroduction on the General Character of 
Mosses 38 
ilected Reports from Chapters of the Tenth 
Century 39 
apter Addresses, New and Revised . . 40 
New Helper in Chemistry 40 
ill Name Your Beetles for You .... 40 
'ORIAL.— The Three Kingdoms of Nature 41 
The Meteorite of Oschansk 42 
An Improved Lamp-Shade 42 
Meteorology for January, 1891 42 
, Astronomical Phenomena for March, 1891 . 43 
j Questions and Answers 43 
I Literary Notes 43 
Medicine and Pharmacy.— The Function of 
Nutrition 44 
Monthly Summary of Medical Progress . . 44 
How the Pathogenic Bacteria Do Their 
Harm 45 
A Lesson in Longevity 45 
ITie Experiment With the Dog 45 
j ■ Megalocephalia, or Swelled Head .... 46 
Medical Miscellany 46 
Publishers' Column „ . 46 
^anrailiar (§eiensc. 
SCIENTIFIC RECREATIONS. 
The automatic pedestrian is a curious little toy, 
interesting from its very simplicity. It consists 
(Fig. 1) of an inclined plane formed from a piece 
of wood and some bent wires, and a small figure 
of tin, the legs of which move freely on a pivot 
of wire, as showed in the enlarged drawing. Two 
other wires passed through the body of the figure 
prevent the legs from moving beyond the length 
of an ordinary step. In its hands is placed a 
piece of wire bent into the shape of a V. This 
serves as a balancing-pole, and when the figure is 
placed on the board it brings the center of gravity 
below its feet(|SO that it will retain its upright 
position. If, now, the "pedestrian" is placed at 
the top of the inclined plane, he starts ofl' and 
walks rapidly down towards the lower end, 
throwing his weight from one foot to the other 
in a quite natural manner. When it is considered 
that there is no machinery at all concealed in the 
figure, the result is quite surprising, but is easily 
explained as the result of the slight oscillatory 
motion given to the figure by the balancing-wire. 
It is, in fact, a pendulum, and as it swings from 
side to side, the point of support is shifted auto- 
matically from one foot of the figure to the other, 
while the weight of the whole causes it to fall, or 
walk down the inclined plane in a very natural 
and amusing manner. 
A VERY pretty stage trick was recently intro- 
duced in a play at a Paris theatre, where certain 
robes were exhibited, which, when lifted from the 
chest in which they were contained, shone with a 
golden or silvery light, and were, apparently, self- 
luminous. This beautiful efiect was obtained by 
placing a powerful electric light underneath tlie 
stage, and reflecting its rays through the stage 
and into the chest, through openings provided for 
the purpose. The chest was filled with a light, 
thin, yellow gauze, which, when lifted out, re- 
flected the light in all directions, in a manner 
analogous to the illuminated fountains and jets 
of water which were such a feature of the last 
Paris Exposition. To obtain a silvery or "moon- 
light" effect, blue gauze was substituted, and a 
piece of blue glass placed before the electric light. 
When the scene was finished, the robes were re- 
placed, the "traps" in the stage and the chest 
closed, and the chest could then be lifted and re- 
moved from the stage, making the illusion com- 
plete. Modern stage eflfects owe much to the dis- 
coveries of science, and especially to the various 
manifestations of electricity, the ease with which 
this agent can be handled and applied, and the 
surprising phenomena exhibited by it, rendering 
it peculiarly adaptable to this pui-pose. 
Brass is, perhaps, the best known and most use- 
ful alloy. It is formed by fusing together copper 
and zinc. Different proportions of these metals 
produce brasses possessing very marked distinct- 
ive properties. 
[Original In POPULAR Science News.] 
STUDIES IN PLANT BIOLOGY. 
BY PROP. JAMES H. STOLLER. 
II. 
THE GREEN MOULD. 
Having studied an example of the one-celled 
plants, which constitute the lowest group of the 
botanical kingdom, the Protophyta, we now pass 
to an examination of one of the simpler multicel- 
lular plants. We choose the green mould {Peni- 
cillium glaucum) yv;\\\\ the appearance of whicli as 
a green growth on decaying organic substances — 
as stale bread, fruit jam, old leather, etc. — every 
one is familiar. The reader can make this study 
a practical one by preparing a paste of flour and 
water, and, having allowed it to stand a few days 
in a moderately warm and not too dry place, no 
matter whether exposed to the light or not, ob- 
serving the mould in the successive stages of its 
growth. A hand magnifying-glass will be of 
much aid in the examination. 
The first appearance of the mould is slight 
whitish patches of film at the surface of the 
liquid. These rapidly extend, become slightly 
elevated, and take on a more opaque look. In 
three or four days they show a bluish green color 
at the center, and the colored area gradually ex- 
tends outward and deepens in intensity. By this 
time the patches have run together, and the whole 
mass seems to float on the surface of the liquid. 
If, now, one blows upon it, a cloud of green dust 
arises. This dust consists of spores. 
Under the microscope a spore is seen to be a 
minute spherule, perhaps one two-thousandth of 
an inch in diameter. It is, in fact, a fairly typical 
plant-cell, consisting of an outer wall, or cell-sac, 
and inner contents of protoplasm. It is essen- 
tially like — indeed, scarcely distinguishable from 
— some of the Protophyta, which, as we have 
learned, consist of nothing more than single cells. 
A spore having fallen into the liquid paste, if it 
be watched — as can be done under proper arrange- 
ments — a full explanation of the appearances 
noted above will be aflforded. The spore increases 
in size, its protoplasm becomes more granular, 
and in a few hours there is a slight protrusion 
of the cell-sac at one place. This protrusion ex- 
tends into an elongated tubular filament, and 
gives off" branches from its sides. Just before the 
places of branching, cross-partitions are formed, 
so that the plant now consists, not of a single 
cell, but of several cells united. Meanwhile other 
filaments have grown out from the spores and 
have given off" branches. These become inter- 
laced with one another and with those that hav« 
grown out from other spores, and so a delicate 
white film, like a bit of loose blotting-paper, forms 
on the surface of the liquid. This film, in botani- 
cal terminology, is a mycelium, and the separate 
branches of which it is made are hyphae. 
At first all the hypliM lie parallel to the surface, 
but after a while some may be seen to hang down 
in the liquid and others to rise vertically into the 
air. The down-growing ones are to play the part 
of absorbents, taking up food matter from the 
