ON SOLAR CHANGES OF TEMPERATURE AND VARIA- 

 TIONS IN RAINFALL IN THE REGION SURROUNDING 

 THE INDIAN OCEAN/ 



By Sir Norman Lockter, K. C. B., F, R. S., and W. J. S. Lockyer, 

 M. A. (Camb.). Ph. D. (Gott). 



The fact that the abnormal behavior of the widened lines in the 

 spectra of sunspots since ISOtt had been accompanied Ijy irregularities 

 in the rainfall of India suggested the study and correlation of various 

 series of facts which might be expected to throw light upon the subject. 



The conclusions already arrived at from bringing together the results 

 of several investigations undertaken with this view may be stated as 

 follows: 



(1) It has been found from a discussion of the chemical origin of 

 lines most widened in sunspots at maxima and minima periods that 

 there is a considerable rise above the mean temperature of the sun 

 around the years of sunspot maximum and a considerable fall around 

 the years of sunspot minimum. 



(2) It has been found from the actual facts of rainfall in India 

 (during the southwest monsoon) and Mauritius, between the years 

 1877 and 1886, as given by Blanford and Meldrum, that the effects of 

 these solar changes are felt in India at sunspot maximum, and in 

 Mauritius at sunspot minimum. Of these the greater is that produced 

 in the Mauritius at sunspot minimum. The pulse at Mauritius at 

 sunspot minimum is also felt in India, and gives rise generally to a 

 secondary maximum in India. 



India therefore has two pulses of rainfall, one near the maximum 

 and the other near the minimum of the sunspot period. 



(3) It has been found that the dates of the beginning of these two 

 pulses on the Indian and Mauritius rainfall are related to the sudden 

 remarkable changes in the behavior of the widened lines. 



(4) It has been found from a study of the famine commission reports 

 that all the famines therein recorded which have devastated India 

 during the last half century (we have not yet carried the investigation 

 further back) have occurred in the intervals between these two pulses. 



^ Reprinted (abridged) from Nature, November 29 and December 6, 1900. 



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