18 



Proceedings of the Royal Physical Society. 



above the two outer pointers of the Plough on a starry 

 night about the middle of October, and the light of the 

 lantern of the lower lighthouse, coincide, and are about due 

 magnetic north." ^ Further : " The village of Grail on the 

 Fife coast, and the east wall of the lighthouse, line together, 

 as nearly as possible — and probably exactly— due north and 

 south. Bell Eock Lighthouse is visible from the North of 



E.N.E. 



W.S.W.X / / / \ \ \ /E.S.E. 



If tlie wind is /rom the S.E., a comparative vacuum is occasioned at the 

 N.W. side. In the diagram it is intended to show this by the directions of 

 the arrows. 



the lighthouse balcony, and St Abb's Head 25 miles from 

 the S.E. side of the same. The new lighthouse of Fidra 

 Island (1885) is to the S.W. of the Isle of May, distant 

 12 miles." 



I do not deem it necessary to dwell at any very great 

 length upon the physical aspects of the island, but only 



1 When the lighthouse tower was erected, the magnetic direction of the 

 compass N. was more to the westward than it is now. The draughtsman 

 has put the magnetic north of the May Island diagram in its present position, 

 and in this he is perfectly correct. — J. Bolam, in lit. 



