NO. 29 VOLCANOES AND CLIMATE — ABBOT AND FOWLE 15 



per square centimeter per minute owing- to the volcanic haze of 1912, 

 the 10 per cent loss of heat incoming from the sun, due to the reflec- 

 tion of this haze to space, would be half compensated. The value 

 0.0045 calorie is so near the difference, 0.002 calorie, found by .Mr. 

 Angstrom to exist between his clear and hazy days, that it seems 

 impossible to say as yet whether the decrease of heat available to 

 warm the earth was not in considerable measure compensated as we 

 have described. 



INFLUENCE OF FORMER HAZY PERIODS ON THE SOLAR 

 RADIATION 



It is only since just before the Krakatoa eruption of 1883 that we 

 have had measurements of the intensity of solar radiation compar- 

 able to those that were available in 1912. From a paper of Prof. 

 H. H. Kimball * we copy the data for the top line of the accompany- 

 ing Fig. 3, which shows the departures of the annual solar radiation 

 received at the earth's surface, as measured at Montpelier and other 

 stations. The smoothed curve (A) of the figure is formed from 

 the combination of these results by adding to twice the value for the 

 year in question the value for the year next preceding and the value 

 for the year next following, and dividing the sum by 4. It is 

 apparent that very great departures from the usual intensity of solar 

 radiation occurred from 1883 to 1887, from t888 to 1893, and from 

 1902 to 1904 respectively. The departure which followed the Kra- 

 katoa eruption is only what we should have expected, but it is inter- 

 esting to find, if we can, the causes of the diminished solar radiation 

 having minima in 1891 and 1903 respectively. 



Considering first the period 1888 to 1893,' undoubtedly the greatest 

 eruption of this period occurred in northern Japan. Bandai-San is 

 a mountain about 5,800 feet high which had shown no sign of 

 activity for about 1,100 years. A subordinate peak called " Little 

 Bandai-San " arose on its northeastern side. On the morning of 

 July 15, 1888, with only a few minutes earthquake as a preliminary 

 warning, Little Bandai-San was blown completely into the air and 

 obliterated. The debris buried and devastated an area of at least 

 30 square miles. An estimate based on the depth of the material in 

 this area indicated that the quantity of earth, rocks and volcanic 

 material reached 700,000,000 tons, and that doubtless the true figure 

 would be much greater still. About 600 people perished horribly, 

 and many more were reduced to destitution. It was with one possi- 



1 Bulletin of the Mount Weather Observatory, Volume 3, Part 2. 



