196 
WA TORE 
[Fuly 1, 1886 
own observations show, the shock loses much of its 
individuality as it travels further from the source. It 
becomes more and more preceded by a vanguard of 
small waves, and, for this reason, seismoscopes of differ- 
ent degrees of sensibility will differ in the time at which 
they chronicle the arrival of the group. Mr. Milne’s 
results, as summarised by him at the end of the paper, 
are too numerous to be taken up in detail. The assiduity 
with which he has pursued these experiments deserves 
the greatest praise, especially as the experiments them- 
selves are of a very high order of difficulty. It is perhaps 
to be regretted that Mr. Milne has not given his attention 
more to perfecting a single series than to multiplying 
results which, as he himself remarks, are often“ most 
discordant.” Seismographs will not tell the truth unless 
they are very well made and very carefully tended. Some 
of the jagged outlines of the curves are much more likely to 
be due to friction and shakiness and want of rigidity in the 
instruments than to any characteristic in the motion of 
the ground; and unless the lithographer has done Mr. 
Milne a serious injustice, there are cases where the 
ground suffers a considerable displacement in a good 
deal less than no time. He has himself observed this in 
one instance, and ascribes it to what must (if his explana- 
tion be correct) be called a faulty mode of setting the 
seismographs. It is not impossible to get results free 
from these defects ; and a single really good set of dia- 
grams would do much to remove the uncertainty which 
now attaches to many of Mr. Milne’s results. 
Besides the experiments with artificial earthquakes, the 
paper describes a laboratory investigation of the sta- 
bility of cylindrical columns standing on a platform which 
vibrates horizontally, and of the velocity of projection of 
detached bodies. The projected bodies were balls, held 
in L-shaped notches at the top ofa vertical wooden post ; 
the post, bent slightly to begin with, was allowed to 
spring; the velocity of projection of the ball was deter- 
mined from its trajectory, while the greatest velocity of 
the post-head was measured by means of a revolving 
plate of smoked glass. The two agreed fairly well, and 
with a nearly frictionless ball supported in this manner 
no other result was to be expected. The late Mr. Mallet 
used to calculate the velocity of the ground’s motion from 
observation of the horizontal distance traversed by pro- 
jected bodies, but the velocity with which a body is 
projected depends too largely on the mode of support, 
and on the amount of adhesion between the body and the 
support, to allow the result to be, in general, of the 
slightest value. With regard to the overthrow of 
columns, it would seem that the author falls into the 
error of supposing that when the resultant force got by 
compounding the weight of the column with its resistance 
to acceleration passes outside the base, the column will 
fall. But since the disturbing force is of short duration, 
all that necessarily happens in such a case is that the 
column will rock; whether it will fall or not is a question 
of much greater difficulty. 
The second paper is a note by Mr. S. Sekiya, “On 
Prof. Ewing’s Duplex Pendulum Seismometer, with 
Earthquake Records obtained by it.” The paper is a 
brief but very clearly written account of a form of the 
duplex pendulum seismograph designed by the present 
writer in 1883, and now in constant use under Mr. 
Sekiya’s care. An earlier form of the instrument has 
already been described in NATURE (vol. xxx. p. 152): 
the latest modification of it was exhibited to the British 
Association at Aberdeen, and will shortly be illus- 
trated in this journal. Its function is to draw on a 
fixed plate a magnified diagram of the ground’s horizontal 
motion ; the figures, which are generally of great com- 
plexity, are given by Mr. Sekiya for a number of recent 
Japanese earthquakes. 
A short paper follows by Mr. E. Knipping, “On the 
Meteorology of Japan,” gathered from observations made 
at twenty-three stations during the year 1883. It men- 
tions that the annual variation of temperature for that 
year in Japan was more than double that of Britain, and 
that changes of 14° C. or 15° C. at one station in twenty- 
four hours are not unfrequent in the spring and autumn. 
A paper by Father Faura, S.J., of Manila, describes 
the Cecchi seismograph—an instrument belonging so 
decidedly to the old school of seismology that, by allow- 
ing its description to appear without criticism, the Society 
at least shows its catholicity of spirit. 
Dr. Dubois contributes some notes on the earthquakes 
of Ischia, and refers to the effects—or rather absence of 
effects—of the earthquakes in excavations there, in support 
of the fact that seismic shocks which do much damage 
on the surface may pass unperceived at a certain distance 
beneath. 
The volume concludes with a catalogue of earthquakes 
registered in the meteorological observatory of Tokio by 
Palmieri’s recording seismoscopes. The list for 1884 
shows the respectable total of seventy distinct disturb- 
ances, and twenty-eight were registered in the first four 
months of 1885. J. A. EWING 
RECENT ADVANCES IN SANITARY SCIENCE 
¢ YGIENE,” in the words of the late Professor 
Parkes, “is the art of preserving health ; that is, 
of obtaining the most perfect action of body and mind 
during as long a period as is consistent with the laws of 
life. In other words, it aims at rendering growth more — 
perfect, decay less rapid, life more vigorous, death more 
remote.” The art of preserving health is correlative with 
the science of prevention of disease, since perfect health 
means the absence of disease and of tendencies to disease. 
Hygiene is thus the art of preserving health and the 
science of preventing disease ; and in taking into account 
recent advances in sanitary science we must consider 
recent acquisitions in our knowledge of the origin, causes, 
and spread of disease, more especially of those diseases 
known as “preventable,” as well as the methods of 
improving the natural conditions or social relations 
surrounding us, which are instrumental in preserving 
health and counteracting disease. 
The etiological relations of all diseases are a subject of 
interest to the sanitarian, but those which have received 
the most attention of recent years, and in which the most 
striking advances of knowledge have either already been 
made, or are imminent in the near future, are perhaps 
Asiatic cholera, typhoid or enteric fever, diphtheria, 
and phthisis or tubercular disease of the lungs. The 
mode of origin and spread of Asiatic cholera has attracted 
great popular attention, both on account of its possible 
introduction into this country from infected districts of 
the Continent, and from the alleged discovery by Koch of 
a Spirillum or comma-Lacillus asserted to be the specific 
cause of this terrible disease. The Reporc of the Govern- _ 
ment Commission consisting of Drs. Klein and Heneage > 
Gibbes, who visited India in 1584 with the object of 
undertaking researches into the etiology of Asiatic — 
cholera, has lately appeared, and in this Report the 
conclusions arrived at by Koch from his own researches 
are very directly traversed. This Report, too, has received 
a very cordial support from a Committee consisting of 
many eminent physicians and physiologists, which was 
convened by the Secretary of State for India for the 
purpose of taking it into consideration. It must be 
apparent, however, to any one who makes an impartial 
study of the literature of the subject, that, if Koch’s” 
organism has not yet been proved to be the actual cause 
of the disease, it has been proved to differ from all other 
organisms asserted to be identical with it, from the fact 
that its growth in various nutrient media is characteristic, 
and serves to distinguish it from all other organisms. As fa 
| as ourknowledge at present extends, difference in manner of 
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