614 
mental observations alone had to be relied on for the determina- 
tion of their origin. These observations, so far as they have at 
present gone, show in a remarkable manner how a large moun- 
tain range absorbs earthquake energy. Thus, it is very seldom 
that an earthquake travelling from the north passes beyond the 
Hakone range of mountains to the south of Tokio, Earthquakes 
having their origin on either side of such a range rarely travel to 
the other side, however large their area of activity on their own 
side may be. The whole of Japan has in this way been divided 
into districts of varying seismic activities. By two separate 
systems of investigation Mr. Milne showed that, if instruments 
of ordinary sensitiveness were distributed throughout Japan there 
would on the average be recorded, at the lowest estimate, over 
1200 shocks per year, or about three shocks per day, which is a 
number greater than that obtained by Prof. Hein for the whole 
world. 
THE last number of the Yownal of the North China branch 
of the Royal Asiatic Society contains a long and learned paper 
by Dr. Bretschneider, of the Russian Legation at Pekin, on 
Chinese Botany. The plan of the work, of which the present 
is only an instalment, is explained as follows. It is divided into 
a general and a particular part. The first, which forms the 
substance of the present paper, begins with a review of the his- 
tory of botany, agriculture, and Materia Medica of the Chinese 
and other Eastern Asiatic nations, and enters into some details 
concerning the most prominent treatises and authors in these 
departments. Inthe same chapter he shows the method em- 
ployed by the Chinese in describing plants and in investigating 
botany and materia medica. Another chapter is devoted to the 
important question of identifying Chinese names of plants with 
‘the scientific botanical names, and to recording the attempts 
made by European scholars to ascertain the botanical names of 
the plants described in Chinese books. The first part will con- 
clude with an alphabetical list of Chinese works, and another of 
Chinese authors quoted in native botanical treatises. In the 
second part, the author will give a history of Chinese domestic, 
ornamental, medicinal, and other plants used for economic pur- 
poses, as far as these have come to the knowledge of botanists. 
The work, it will thus be seen, involves a vast amount of laborious 
research in European as well as Chinese literature. The present 
number contains chapters on the history of the development of 
botanical knowledge among the various peoples of Eastern Asia, 
and on the scientific determination of the plants mentioned in 
Chinese works, together with an index of Chinese writers on 
botany, and an appendix on celebrated mountains in China, 
which are frequently mentioned in Chinese botanical works, 
Dr. Guppy, R.N., gives some notes on the hydrology of the 
Yangtsze, Yellow River, and Peiho, and also on the geology of 
Takow in Formosa, The other paper is by Father Dechevrens, 
S.J., on the climate of Shanghai. The number closes with a 
list of the ferns found in the yalley of the Foochow River. 
THE fourth number of the Memoirs of *he Science Depart- 
ment of the University of Tokio is a monograph on the geology 
of the environs of Tokio, by Prof. Brauns; while the fifth con- 
tains a paper by Prof, Mendenhall on the force of gravity at 
NALORE 
Tokio and on the summit of Fujiyama. Dr, Naumann, the 
head of the Japanese Geological Survey, has recently published 
a monograph on Japanese elephants. The writer has found 
remains of these mammals in yarious widely separated districts. 
This paper will be found in vol. xxviii. of the ‘ Palonto- 
graphica,’”’ published by Fischer of Cassel, and is entitled | 
“Ueber Japanische Elephanten der Vorzeit.” 
In the Belgian Academy, M. Plateau has lately called atten- 
tion to a small illusion, He describes an arrangement which, 
at first sight, he says, might be thought capable of realising per- 
petual motion. A capillary tube is inserted obliquely in distilled | 
[April 27, 1882 
water, so that the latter nearly fills it. Into this liquid column, 
at the top, dips the small orifice of another tube, which reaches 
a little way in the same oblique direction, then turns downwards, 
the vertical portion being wider, and not reaching the water. 
Suppose this bent tube filled with water. It then formsa siphon, 
the shorter branch of which is immersed in a liquid in equili- 
brium, while the longer descends several centimetres below the 
surface of that liquid. Does it not appear as though the water 
should flow incessantly through the siphon, and, regaining the 
vessel, be engaged in perpetual circulation? As a matter of fact, 
the water is drawn upwards in the vertical portion of tube till its 
free surface reaches a part of the oblique part of the same tube, 
when it stops. M. Plateau accounts for the effects by suction 
exerted by the small concave liquid surface between the two 
tubes 
A NEW dynamo-electric machine, recently brought before the 
Belgian Academy by M. Pliicker, has the peculiarity that a 
solenoid is substituted for the electromagnet as an organ for ex- 
citation of the induction currents. The horizontal coils of the 
solenoid, which is of special form, are traversed by the currents 
produced by the machine itself, The apparatus rotated within 
the solenoid is a wheel with coils arranged nearly like those of 
the Gramme ring. The whole system is inclosed in an iron 
armature meant to increase the inductjve action. M. Pliicker 
states that he replaced the solenoid with electromagnets, and the 
apparatus produced the same effect. He seems merely to claim 
the advantage of less weight and volume. 
A SERIOUS difficulty recently occurred at Berlin, in connection 
with a system of supply of ‘‘ ground water ” by ‘‘natural filtra- 
tion” (a part of the Berlin water supply having been taken since 
1877 from near the Tegeler Lake, by means of a series of twenty- 
three wells running parallel with the shore; the water was 
pumped into a small covered reservoir, then to another at 
Charlottenburg, 6 or 7 kilom. distant, whence pumps supply the 
city), Complaints arose on account of the water, though clear 
at first, getting turbid ere Jong, and depositing an cchreous sedi- 
ment found to consist of amorphous bydrated oxide of iron, but 
also very largely of algze, dead and alive ; Crenothrix kiithniane 
(a plant of thready form), being most noticeable. The source of 
the plants could neither be located in surface-water, nor in 
the neighbouring lake; and there is reason to believe the 
plant lives and grews in the ground itself. After sundry 
attempted remedies it seemed that artificial filtration would 
be necessary. It was found that water brought directly 
from the wells to the filter, gave, after filtration and rest, the 
usual deposit. But by exposing this well-water to the air, so 
that all the iron was oxidised and depcsited before filtration, it 
was possible to get a filtered water which remained clear ; though 
it is not known whether this filtered water was really free of 
spores, and would continue clear after being in contact with the 
iron of the service. Iron seems essential to the existence of 
Crenothrix, and is proved to be present in its threads. The 
filter-sand was very much fouled, and, because of the difficulty 
of keeping out spores, it was thcught best to abandon the wells 
altogether, and to use water taken directly from the lakes and 
filtered in the usual way. Prof. Nichols (who reports these 
facts in the Franklin Institute Fowrnal) refers to somewhat 
similar troubles having been experienced at Halle, and at a town 
in the east of Massachusetts. 
THE following subjects are announced by the Belgian Academy 
for prize competition :—In mathematical and physical sciences : 
Establish, by new experiments, the theory of reactions of bodies 
in the so-called nascent state. Prove the accuracy} or falsity of 
the following proposition by Fermat: To decompose a cube into 
two other cubes, a fourth power, and generally any power into 
two powers of the same name, above the second power, is im- 
