DO VOLCANIC EXPLOSIONS AFFECT OUR CLLM.VTE? 



195 



The magnificent volcano of Colima, in 

 Mexico (height, 3,960 meters, or 13,000 

 feet), had a period of great activity from 

 February 15 to Alarcli 24, 1903, during 

 which there were maximum eruptions on 

 12 days. In a photograph taken ^larch 

 7, 1903, the cokmin of ashes seems to 

 reach a height of about 17 miles. 



It is clear, I think, from these records 

 that the decrease of solar radiation from 

 1888 to 1893 had much volcanic action to 

 cause it. including Bandai San, Mayon, 

 in the Philippines, \'"ulcano Island, and 

 others; and that the depression, whose 

 maximum was in 1903, was attributable 

 to the terrific explosion of Santa Maria, 

 in Guatemala, on October 24, 1902, rein- 

 forced by the later eruptions of Colima, 

 in Mexico, of which a photograph is 

 given on page 198. 



Temperature Departures [Cejit (grade). 



DOES the; voi,c.\xic ii.\zk troduce cold? 



I have made some preliminary study 

 to determine if the haziness produced 

 by volcanoes causes a decreased temper- 

 ature at the earth's surface. 



Taking the year 19 12, I find from the 

 international ten-day mean values pub- 

 lished by the German Marine Observa- 

 tory that the high altitude stations of 

 southwestern Europe, namely. Pic du 

 Midi, Puy de Dome, Brocken, Schnee- 

 koppe. Santis. and Hoch-Obir, give a 

 very marked indication of a decrease in 

 temperature with respect to the normal 

 beginning about the middle of July. 

 The six stations I have named are very 

 consistent with one another in this indi- 

 cation, and the following table, giving 

 their mean result, shows the effect very 

 clearly : 



ilfean 0/ Six Jfountaiti Stations, igi2. 



Stations in our own country, however, 

 are not so consistent. I have chosen some 

 where the cloudiness is small so as to 

 avoid that complication. The stations 

 chosen are arranged in the following 

 table with regard to whether their tem- 

 perature departures* are increasingly 



negative after July, and thus support the 

 indication of the high mountain stations 

 of southwestern Europe, or not. It is 

 interesting to see that Leadville and 

 Flagstaff, which are both very high sta- 

 tions, fall in the first category. 



*These departures are in Fahrenheit degrees. 



