Proceedings of the British Association. Ill 



Thursday, \§th June. 

 Section A.— MATHEMATICAL AND PHYSICAL SCIENCE. 



The President, G. B. Airy, Astronomer Royal, not being in the 

 Section when it opened, Prof. Forbes, one of the Vice-Presidents, 

 took the chair. 



Sir J. F. "W. Herschel rose and stated, as a Report ' On the 

 Nomenclature of Stars,' that the only reason for continuing this 

 committee was to keep alive a small grant to pay for certain charts, 

 the amount due for which, owing to the death of Mr. Baily, had not 

 yet been ascertained. 



Mr. Dent then addressed the Section on his proposed method of 

 suspending a Ship's Compass. An account of this instrument was 

 communicated to the Association at its last meeting in York. Mr. 

 Dent now read extracts from a report of the working of this compass 

 during six months at sea, as ordered by the Lords of the Admiralty, 

 the amount of which was, that his compass was found " to be 

 extremely sensitive, moving exactly and admirably with the ship's 

 head, when the helm was put hard-a-port and hard-a-starboard : while 

 the other compasses with which it was compared were always in 

 arrear." 



Dr. Lloyd asked whether Mr. Dent was aware, that the principle 

 of his suspension bed had been successfully adopted by Mr. Fox, in 

 an instrument which he had constructed for taking the inclination 

 many years since. — Mr. Dent was aware that Mr. Fox had adopted 

 that mode of suspending a dipping needle, for it was he himself who 

 executed the instrument for Mr. Fox ; but this was the first attempt, 

 he believed, ever made to suspend the ordinary azimuth compass in 

 that manner. 



Dr. Scoresby described a large magnetic machine which he had 

 constructed, with some results of its action. The principal part of the 

 machine consists of two cases, or fasciculae of magnetic bars, of un- 

 usually large dimensions, on principles which may be thus summarily 

 stated : — 1. That magnetic bars designed for large combinations, may 

 be conveniently constructed of various pieces ; that the separation of 

 a long bar, say of three or four into several portions, is not disadvan- 

 tageous in regard to power, and that the resulting power is similar, 



