6o6 POPULAR SCIENCE MONTHLY. 



The data were collected for New York City and the city of Denver, Col., 

 and although the climatic conditions of the two cities are very different, 

 it is in no sense a comparative study for them. In fact, so few data (two 

 hundred and sixty suicides) were procurable for the western town that 

 but little weight is given to conclusions based upon them, compared 

 wi th the much greater number for New York City, and the study of the 

 former is only incidentally mentioned. 



The method of procedure was as follows: In order to procure the 

 proper data of suicide for the city of New York the records of the 

 coroner for five years were carefully gone over (some 28,000 separate 

 death certificates), disclosing the particulars of 1,962 suicides, and the 

 exact number (varying from to 9) tabulated for each of the 1,826 days 

 of those years. Next the police records for the same five years were 

 studied, and the number of unsuccessful attempts for each day noted. 

 This record is quite complete, since in the eyes of the law one attempt- 

 ing suicide is a criminal, and must be so branded on the books. From 

 these two sources were obtained the exact number of persons who for 

 each day of the period covered were of suicidal intent, unless some un- 

 successful attempt escaped the surveillance of the police. In the present 

 article neither age, sex, nationality, nor occupation is considered; simply 

 the fact that some one wished to die by his own hand — for the five years, 

 2,946 in all for the city of New York. 



When the data of suicide had thus been tabulated, the meteorological 

 basis for the study was obtained from the records of the United States 

 Weather Bureau. At the New York station (Denver for the Denver 

 study) were copied the mean temperature, barometer and humidity, the 

 total movement of the wind, the character of the day and the precipita- 

 tion for each of the 1,826 days of the period considered, and placed op- 

 posite the already tabulated number of suicides. Then, by a somewhat 

 laborious process of tabulation, the exact percentage of days which were 

 recorded at the Weather Bureau under each of the seventy-seven definite 

 meteorological conditions represented by the accompanying figures was 

 computed. That is, the exact percentage characterized as 'clear,' as 

 'partly cloudy,' or 'cloudy,' as having some or no precipitation (without 

 considering the amount), as having had a mean temperature between 

 zero and five degrees F., between five and ten degrees, and so on for each 

 one of the designated groups for temperature, barometer, humidity and 

 wind. Now, it may be readily seen that these percentages represent the 

 normal or expected occurrence of suicide for each meteorological group 

 if the weather had no effect. For instance, if thirty per cent, of the days 

 are found to be characterized as 'clear,' we should expect that same per- 

 centage of suicides for 'clear' days plus or minus the percentage due to 

 probable error from accidental causes (which with the number of data 

 used would be very small) if the character of the day had no influence on 



