PROCEEDINGS 
OF THE 
ROYAL SOCIETY OF EDINBURGH. 
vol. ix. 1875-76. No. 95. 
Ninety-Third Session. 
Monday , tith March 1876. 
Sir WILLIAM THOMSON, President, in the Chair. 
The following Communications were read : — 
1. The Annual Periods of Thunder (with Lightning), Light- 
ning (only), Hail, and Snow, at Oxford. By Mr Buchan. 
During the twenty-one years ending 1873, the maximum period 
of thunder with or without lightning, at Oxford, extended from 
about 9th April to the end of October, the middle of the period 
being the first week of July; the three highest days taken 
consecutively being those immediately preceding the summer 
solstice. During the five months from November to March, only 
thirteen cases had occurred during the period. Lightning, on the 
other hand, had its maximum period from May to November, — 
particularly during August, September, and October. The maxi- 
mum period of hail was during the first six months of the year ; 
whereas, during the second half of the year, very few cases 
occurred. The snow period extended from the middle of October 
to the middle of May, — most falling from December to March, — 
the absolutely highest month being March. 
Thus, thunder with lightning , at Oxford, closely follows the sun, 
the middle of the period being only about ten days after the 
VOL. IX. 
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