Photo by R. R. Rivera. By courtesy of The University of Chicago Press and the Journal of Geology 



MOUNT COIvIMA IN ACTION, MARCH 7, I903 



The column of ashes seems to reach to a height of 17 miles, or 89,760 feet. It is pre- 

 suined that this notable eruption was largely responsible for the decrease in solar radiation 

 noticeable in 1903 (see page 195). 



influenced the march of temperature in 

 the United States. When we take the 

 march of temperature for the whole 

 world the apparent effect is not so strik- 

 ing, but in this case there are so many 

 conflicting influences at work that it is 

 perhaps too much to expect so good an 

 agreement. 



In view of this slight preliminary 

 study of temperatures, it seems to me 

 that the question of the effect of vol- 

 canic haze on terrestrial temperature is 

 well worth serious consideration. 



Although a large group of stations 

 may, by their contrary local influences, 



mask the influence of the haze, / helicve 

 it zvill be found eventually that tempera- 

 tures are influenced perhaps as much as 

 several degrees by great periods of hazi- 

 ness, such as those produced by the vol- 

 canoes of 188^, 1888, and ipi2. 



Certainly an agency capable of send- 

 ing vast clouds of dust to a height of 20 

 miles in the air, there to be distributed 

 by the winds all over the world, and to 

 remain in suspension for months or 

 years, causing the decrease of the direct 

 radiation of the sun by as much as 20 

 per cent, is a climatic influence not to be 

 iqrnored. 



