216 Proceedings of the Royal Society of Victoria. 



had said, when mistakes in navigation were made, people 

 generally looked out for currents to excuse them, but in nine 

 cases out of ten it was caused either by manifest carelessness, or 

 by some defect in the conij^ass. In some parts of the world — and 

 this was the case on the Australian coast — certain classes of fogs 

 disturbed the compass very much, and sometimes dangerously so. 

 There was no doubt about this being a fact, although it was not 

 generally believed, because many Captains of ships had been in 

 fogs and had never noticed it. Certain fogs occurred sometimes 

 in Port Phillip that threw the compass off a great number of 

 degrees and when he had been first informed of this, a few years 

 ago, he had been at a loss to account for it. But all old and 

 trustworthy mariners spoke of having experienced it, and lie 

 thought it quite possible, because in this country a certain kind 

 of fog sometimes prevailed on the mountains and plains and over 

 the Bay that seemed to form an electric couple with the surface 

 of the earth, or rather with a layer of atmosphere varying from 

 five to ten feet thick, and if during the continuance of the fog, 

 one explored between the surface of the earth and say five or six 

 feet above it, and perhaps five or six feet above that, it would be 

 found that there was a space with scarcely any tension whatever, 

 whilst below there would be a tremendously strong positive 

 tension, and above a tremendously strong negative tension. In 

 fact, one would imagine that were very much more disturbance 

 to take place, there would be flashes of lightning. This state of 

 things would continue for some hours, and then all would become 

 balanced again, and the two layers would be equally electrified. 

 He had experienced this some three or four times. He had read 

 a paper a good many years ago, giving some observations he had 

 made on Mount jNIacedon. These observations were always made 

 in a fog. The registrations at the Observatory made with the 

 electrometre showed signs of this state of the atmosphere existing 

 for short periods of time. From this it would be easy to see 

 that some fogs must disturb a ship's compass, and it was only 

 fair to captains of vessels that this should be known. 



A Member said that an old resident of Apollo Bay had once 

 remarked to him, that sometimes the weather at that place was 

 so bad that it turned the compass round, and assured him that in 

 certain fogs compasses were quite unreliable. 



Mr. E. F. J. Love, M.A., read portions of a letter received by 

 him from Sir George Stokes, President of Royal Society of 

 London, concerning the Gravity Survey of Australia. 



Mr. Ellery said he had received a letter a week or two ago 

 from Mr. Wipple, of Kew, who said the pendulums were being 

 made ready to be sent out. In a previous communication, he 

 (Mr. Ellery) had mentioned that the Council had voted a sum to 



