Wakelin. — Local Variations in Gravity. 465 



There is one very exceptional station on the north coast of Banffshire, near 

 the village of Portsoy, at which the deflection amounts to 10", so that if 

 that village were placed on a map in a position to correspond with its 

 astronomical latitude, it would he 1,000 feet out of position ! There is the 

 sea to the north, and an undulating country to the south, which, however, 

 to a spectator at the station does not suggest any great disturbance of 

 gravity. A somewhat rough estimate of the local attraction from external 

 causes gives a maximum limit of 5", therefore we have 5" unaccounted for, 

 or rather which must arise from unequal density in the underlying strata 

 in the surrounding country. In order to throw light on this remarkable 

 phenomenon, the latitudes of a number of stations between Nairn on the 

 west, Fraserburgh on the east, and the Grampians on the south were 

 observed, and the local deflections determined. It is found that the deflec- 

 tions diminish in all directions, not very regularly certainly, and most 

 slowly in a south-west direction, finally disappearing, and leaving the maxi- 

 mum at the original station at Portsoy." * 



Professor Maxwell believes the ether to be made up of rotating corpus- 

 cules j^cZ in space. That the ether is composed of rotating corpuscules is 

 also the expressed opinion of Mr. Preston, who has made a special study of 

 the ether. Sir William Thompson has shown that magnetic attraction is a 

 rotational effect. Sir John Herschel expresses the opinion that the ether is 

 composed of corpuscules, and says in a very decided manner that they must be 

 fixed in space, and that they may rotate. The writer of this paper had ex- 

 pressed views in strict accordance with these just given. He has endea- 

 voured and still endeavours to show that gravitation is a rotational effect, 

 and, if so, that the ether, or " electric fluid," is the physical agent producing 

 gravitation. Now, as the ether penetrates all bodies and comes in contact 

 with them the velocity of rotation of the corpuscules becomes gradually 

 much reduced by this contact. Eventually these corpuscules combine with 

 the bodies they penetrate, probably making them more dense and also 

 adding to their mass and bulk. Solid rock would have a greater effect in 

 reducing the velocity of rotation of the ethereal corpuscules than earthy or 

 gravelly beds. Consequently all the striking solid features of the earth 

 would become rather exaggerated than reduced by the direct action of the 

 ether alone. " The Uniformitarian Theory " in geology declares that the 

 basis upon which it stands is ' ' that the continents have always been con- 

 tinents and the oceans oceans." The great features of the earth " persist." 

 Whatever great features now exist — as the Himalayas and the Alps, the 

 deep basins of the Atlantic and the Pacific — have always existed in their 

 characteristic features. 



* See Article "Earth" (figure of) in the Encyclopaedia Britannica, by R. E. Clark. 



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