180 
cloudy, rainy and clear—presents, I believe, 
a genuine surprise (see Fig. 3). This 
figure is to be interpreted in the same man- 
ner as the others. Fromit wesee that mis- 
demeanors are less frequent upon cloudy 
and rainy days (latter under ‘ Precipitation ’ 
marked ‘ + .01’ in.) than upon those which 
we are accustomed to consider more agree- 
able. In fact, of all the classes of data 
studied, that for error in banks is the only 
one showing an opposite result. Reference 
to the curves shows that for assault by 
males (Assault M) the greatest excess oc- 
curred upon days characterized by the 
Weather Bureau as partly cloudy. Such 
days have from 4/10 to 7/10 of the hours 
from sunrise to sunset obscured, fair days 
having more than that amount of sunshine 
and cloudy days less. 
Perhaps the most surprising curve is that 
for suicides, showing as it does that those 
who are weary of life choose the fair day, 
upon which there is no precipitation as 
the time for ending an unhappy existence. 
This, together with the fact that the months 
of May and June show the fullest record of 
suicides of any of the year, is directly con- 
tradictory to what seems to be the accepted 
opinion upon such matters. Perhaps fiction 
is largely responsible for the prevailing idea, 
and fiction would certainly lose much of its 
thunder if the proverbial gloomy weather 
could not be brought in for tragic effect. 
The prevailing climate may, however, in- 
fluence these results, as the study for 
Denver (see ‘Suicides’ Denver upon the 
figure), where cloudy days are something 
of a rarity, their effect seems to have been 
more disastrous upon the suicide. There 
an excess of 32% is indicated for such days. 
The social conditions there, are, however, 
somewhat peculiar, as the population con- 
tains a large number of people who have 
gone to the region in search of health, which 
the sunshine was depended upon to restore, 
and the discouragement of even a brief dep- 
SCIENCE. 
[N.S. Von. X. No. 241. 
rivation of its presence was too great to be 
borne. Even the death rate is shown by 
the curves to be slightly higher during 
bright weather, although the difference for 
days of varying character is not great. 
Perhaps the most interesting general con- 
clusion to be drawn from the study is that 
during those meteorological states which 
are physically exhilarating, excesses in de- 
portment, in the ordinarily accepted sense 
of the word, prevail to an abnormal extent, 
while death and irregularities in mental 
processes (error in banks) are below expect- 
ancy. During such weather conditions, 
without doubt the quality of the emotional 
state is more positive than under the re- 
verse conditions, but the results seem to 
show that in the long run an excess of 
energy is a more dangerous thing, at least 
from the standpoint of the police court, 
than the worst sort of a temper with no 
energy. 
Epwin G. DEXTER. 
SCIENTIFIC BOOKS. 
SOME RECENT WORKS ON MECHANICS. 
Theoretical Mechanics, An Introductory Treatise 
onthe Principles of Dynamics, with Applications 
and Numerous Examples. By A. EK. H. Love. 
Cambridge, At the University Press. 1897. 
8vo. Pp. xv + 379. 
Vorlesungen tiber theoretische Physik von H. 
von Helmholtz. Herausgegeben VoN ARTHUR 
Konia, Orro KRriGAR-MENZEL, FRANZ 
RIcHARZ, CARL RUNGE. Band I., Abtheil- 
ung 2. Die Dynamik discreter Massen- 
punkte, herausgegeben von Otto Krigar Men- 
zel. Leipzig, Verlag von Johann Ambrosius 
Barth. 1898. 8vo. Pp. x + 380. 
One of the most original and suggestive of 
recent works on theoretical mechanics is the 
treatise on dynamics of Professor Love. The 
merits of this important book arise naturally 
from the author’s point of view, and we are pre- 
pared to expect something more than stereo- 
typed forms on reading in his preface that ‘‘ The 
works which have been most useful to me in 
