PKOGEESS IN ASTEONOMY. 145 



the "magnetic storms"' observed at Toronto, luit at once attributed 

 them to solar influence, the two cycles running concurrently. It is 

 now universally recognized that terrestrial magnetic efl'ects, including 

 auroraj, minutely echo the solar changes. 



The eleven-year period is not one to be neglected. 



Next comes the inquiry in relation to meteorology. Sir William 

 Herschel, in the first year of the century, when there were practically 

 neither sun spot nor rainfall observations available, did not hesitate to 

 attack the question whether the price of wheat was affected by the 

 many or few spot solar condition. He found the price to be high 

 when the sun was spotless, and vice versa. 



By 1872, however, we had both rainfall and sun-spot observations, 

 and the cycle of the latter had been made out. Meldrum, the most 

 distinguished meteorologist living at the time, and others pronounced 

 that the rainfall was greatest at sun-spot maximum, and, further, that 

 the greatest number of cyclones occurred in the East and West Indies 

 at such times. 



This result with regard to rainfall was not generally accepted, but 

 Chambers showed shortly afterwards an undoubted connection between 

 the cycles of solar spots and barometric pressure in the Indian area. 



By means of a study of the widened lines observed in sun spots an 

 attempt has been recently made to study the temperature history of 

 the sun since about 1877, and the years of mean temperature and when 

 the heat was in excess (+) and defect (— ) made out have been as 

 follows: 



HEAT CONDITION. 



Having these solar data, the next thing to do was to study the Indian 

 rainfall during the southwest monsoon for the years 1877-1886, the 

 object being to endeavor to ascertain if the + and — temperature 

 pulses in the sun were echoed by + and — pulses of rainfall. The 

 Indian rainfall was taken first because in the Tropics the phenomena 

 are known to be the simplest. It was found that in many parts of 

 India the + and — conditions of solar temperature were accompanied 

 by + and — pulses, producing pressure changes and heavy rains in 

 the Indian Ocean and the surrounding land. These occurred generally 

 in the first year following the mean condition; that is, in 1877-78 and 

 1882-83. 



The rainfalls at Mauritius, Cape Town, and Batavia were next col- 

 lated to see if the pulses felt in India were traceable in other regions 



SM 1900 10 



