perature.

But it is also directly affected by these causes, as I shall now
proceed to show. In one of the principal London prisons the average
prison population during the months of June, July and August for the
five years ended August, 1889 was 1,061, and the daily average number
of punishments amounted to 9 and a fraction per thousand. The average
population during the winter months of December, January, February,
for the five years ended February, 1890, was 1009, and the daily
average number of punishments amounted to 7 and a fraction per
thousand. According to these statistics, we have an increase of 2
punishments per day, or 12 per week (omitting Sundays) to every
thousand prisoners in the three summer months as compared with the
three winter months. In other words, there is a greater tendency among
the inmates of prisons to commit offences against prison regulations
in summer than in winter. In what way is this manifest tendency to be
accounted for? If prisoners were free men living under a variety of
conditions, and subject to a host of complex influences, it would be
possible to adduce all sorts of causes for the existence of such a
phenomenon, and it would be by no means a difficult matter to find
plausible arguments in support of each and all of them. But the almost
absolute similarity of conditions under which imprisoned men live
excludes at one stroke an enormous mass of complicating factors, and
reduces the question to its simplest elements. Here are a thousand men
living in the same place under the same rules of discipline, occupied
in the same way, fed on the same materials, with the same amount of
exercise, the same hours of sleep; in fact, with similarity of life
brought almost to the point of absolute identity; no alteration takes
place in these conditions in summer as compared with winter, yet we
find that there are more offences committed by them in the hotter
season than in the colder. In what way, except on the ground of
temperature, is this difference to be explained. The economic and
social factors discussed by us in connection with the increase of
crime do not here come into play. All persons in prison are living
under the same social and economic conditions in hot weather as well
as in cold. The only changes to which they are subjected are cosmical;
cosmical causes are accordingly the only ones which will account
adequately for the facts. Of these cosmical causes, temperature is by
far the mo