340 



TRANSACTIONS OP SECTION A. 



Excepting the rainfall minimum in 1875 the minima for rainfall follow solar 

 maximum and minimum by one and a half or two years. The rainfall maxi- 

 mum between the minimum are more irregular. 



The earthquake maxima follow the solar maxima by two years. The earth- 

 quake minima follow the solar minima by two or three years. 



The droughts recorded in Jamaica history are as follow, see Long, Vol. III., 

 p. 615 : ' From October 1768 to May 1870 was the longest and severest drought 

 ever remembered in the island.' In 1786 there was another great drought 

 (Beckford, p. 63). Again, from the end of 1839 to the spring of 1841, and, 

 lastly, in 1845. We thus get the following table : — 



Average ... 2 years. 



Here again we see the droughts followed the solar maximum and minimum 

 by about two years. 



6. Great Boundary Waves : Parallactic Tides set up in the Bottom Layers 

 of the Sea by the Moon. By Professor O. Petterson. 



TUESDAY, SEPTEMBER 5. 



Discussion on Stellar Distribution and Movements. Opened by 

 A. S. Eddington, M.A. — See Reports, p. 246. 



Department of General Physics and Astronomy. 



The following Papers were read : — 



1. Corpuscular Radiation. By Professor W. H. Bragg, F.R.S. 



Corpuscular radiation may be defined as consisting of ' entities ' or ' quanta,' 

 each moving in a straight line with uniform velocity and unchanging propeities 

 unless impressed forces cause a change. It is a separate question whether corpuscular 

 radiation is necessarily material. The a and £ rays are corpuscular, but not sound 



