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BOSTON JOURNAL OF CHEMISTRY. 
Volume XXIV. 
BOSTON, SEPTEMBER, 1890. 
Number 
CONTENTS. 
Familiar Science. — Rock-Boring Marine Ani- 
mals 129 
Some Experiments in Electric Induction . 129 
Liquid Gases 130 
Geological Formation of the Earth — Its 
Evolution from Chaos to Order . . . 131 
Fertilization of Cypripedium Calceoliis . . 131 
The Star Mizar 132 
Scientific Breveties 132 
Practical Chemistry and the Arts. — Some 
Uncommon but Useful Metals .... 132 
Two Carbon Compounds 133 
Aboriginal Carpentry 134 
Industrial Memoranda 134 
The Out-Door World. — Some Notes on 
Thelyphonus Giganteus, Lucas .... 134 
Snakes Swallowing Their Young .... 134 
Wanted — Advice About Traps 135 
A Good Plan 135 
Southern Insects . . / 135 
Excellent Chapter Work 135 
About Grasses ; . 135 
Editorial. — The Alcohols ....... 138 
Brief Studies in Biology 138 
Meteorology for July, 1890 139 
Astronomical Phenomena for September, 1890 140 
Questions and Answers 140 
Literary Notes 141 
Medicine and Pharmacy. — A Physiological 
View of the Eight-Hour Movement . . 141 
A Consideration of Some of the Parts of a 
Microscope Stand 141 
Increasing the Mobility and Power of the 
Musician's Ring-Finger 142 
Montlily Summary of Medical Progress . . 143 
Autographism 144 
* Medical Miscellany 144 
Publishers' Column 144 
Banjiliar Scieijce. 
ROCK-BORING MARINE ANIMALS. 
It has long been known that certain marine 
animals, particularly the sea-urchins, have, 
apparently, the power to dissolve or excavate 
holes in the rock bordering the sea shore, 
thus making a sort of nest for themselves. 
In some localities the rocks are fairly riddled 
with these holes, and this not only in the soft 
and easily dissolved limestone, but in the 
hardest granite and lava. Fig. i shows a 
colony of these curious little animals, as left 
by the receding tide. The way in which 
these holes, or cavities, in the rocks are 
formed is a matter of some dispute, and in a 
recent paper in the American Naturalist, 
Mr. Walter Fewkes gives an interesting 
resume of the ditferent theories advanced. 
In Fig. 2 is shown a sea-urchin, covered 
with the characteristic spines, (A), and at B 
an enlarged view of the mouth, or what 
answers for that organ. Some naturalists 
suppose that the cavities in the rock are 
produced by the sharp points of the spines 
with which the animal is covered, slowly 
clipping away the rock like the action of a 
file. Others consider that the powerful teeth 
are the active agent — a supposition which is 
strengthened by the fact that the stomach and 
intestines of the sea-urchin are found to contain 
minute fragments of rock. Another theory 
attributes the work to the combined action 
of the spines and teeth. The more plausible 
theory that the sea-urchin secretes a liquid 
capable of dissolving stone, seems to be dis- 
proved by the fact that the cavities are found 
in the insoluble granite and gneiss as well as 
the more easily soluble limestone. 
It has been noticed that the " kettle-holes," 
or cavities worn in the rock by the action 
of stones rolled about by the waves, are a 
favorite resting-place for the sea-urchins, who 
often cover the sides with their nests. One 
of these kettle-holes thus occupied is shown 
in Fig. I. It has even been supposed that 
the kettle-holes themselves often have their 
origin from the small cavity of a sea-urchin, 
which is afterwards enlarged by the action 
of the waves. 
Fig. I. 
The remarkable power of penetrating and 
destroying hard substances possessed by the 
sea-urchins, in common with numerous other 
fragile forms of life, is certainly a most mys- 
terious one, and still awaits a satisfactory 
explanation. The soft, yielding bodies of 
these animals seem poorly adapted to wear 
away such refractory substances as stones and 
rocks, but it is probably another instance 
of the power of patience and perseverance. 
In whatever way the sea-urchin excavates his 
nest, the process goes on constantly ; he has 
nothing else to do, and by constant applica- 
tion of the means with which nature has 
Fig. 2. 
provided him, he toils on, night and day, 
without rest or holidays, until he finally 
attains the desired result, which is so aston- 
ishing to the less industrious human animals. 
SOME INTERESTING EXPERIMENTS 
IN ELECTRIC INDUCTION. 
A correspondent of La Nature de- 
sciibes some novel and interesting experi- 
ments which may be performed with a 
common induction coil and an incandescent 
electric lamp. 
In Fig. I in the engraving, two fine spiral 
wires are attached to the poles of the coil, 
e.ich supporting an electric lamp. When 
the coil is set in action, the two lamps will 
not only be illuminated, but will be attracted 
towards each other. To show the attraction 
properly the lamps should be attached to very 
flexible wires, and placed about a quarter 
of an inch apart. Care should also be taken 
that no sparks pass directly between the wires 
or metallic sockets in which the lamps are set ; 
the action is strictly inductive. The same 
phenomena take place when one lamp is 
attached to the coil and the other is held in 
the hand, (Fig. 2). A single lamp attached 
to one pole of the coil (Fig. 4) also becomes 
luminous, even when there is no connection 
