Page:Popular Science Monthly Volume 55.djvu/679

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INFLUENCE OF THE WEATHER UPON CRIME.
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respiratory processes, but probably, as shown by these curves, more largely to the dryness of the atmosphere, as indicated by low humidity. I hope at some future time to verify or disprove this supposition by a comparative study made at some lower altitude.

Character of the Day.[1]—Fig. 6 shows the relation between the expectancy of crime, based upon the actual per cents of cloudy, partly cloudy, and clear days (records of nineteen years), and its actual occurrence. The disagreements are very slight, although a slight excess of murders is shown for cloudy days.

Summary.—Fig. 1 shows at a glance no generally prevailing meteorological conditions to which can be ascribed, with any degree of certainty, the monthly variations of crime.

Fig. 2 shows that high velocities of wind seem to increase to a marked extent the tendency to crime. For the highest velocities increasing the probability twenty times (two thousand per cent). Fig. 3 shows that high temperatures seem to have the same effect, that of between 90° Fig. 6. and 100° increasing the probability one hundred per cent.

Fig. 4 fails to show that barometric changes are accompanied by any marked excesses in crime.

Fig. 5 shows that low conditions of relative humidity are attended with very marked excesses, those below thirty increasing the probability of suicides eleven times (eleven hundred per cent).

Fig. 6 fails to show that the character of the day has any considerable effect.

Considering briefly, in conclusion, the results of the foregoing study, and comparing them with a somewhat similar one for children,[2] we may safely conclude that the tendency to homicide varies with those meteorological conditions which bring about an emotional state necessitating a considerable discharge of motor stimulus. The same conditions which bring about irritability and unruliness on the part of the child accompany suicidal tendencies.

This supposition is upheld by the fact that suicide is less common in the colder climates, where the metabolic processes are slow, and


  1. By the United States Weather Bureau days are characterized as "cloudy" when for 0.8 or more of the possible hours of sunshine the sun is obscured; "partly cloudy" when from 0.4 to 0.7 inclusive is obscured; and "clear" when 0.3 or less.
  2. See The Child and the Weather, Pedagogical Seminary, April, 1898.