Mr Alger on New Localities of Bare Minerals. 59 



heated land in that meridian rendering the air flowing over 

 to that pole more dry, and consequently I'edueing its elec- 

 tricity. 



The daily variation of the needle is probably owing to the 

 difference in the quantity of vapour rising from the earth dur- 

 ing the night and day. 



I believe that experiments with electrical kites, in the frigid 

 regions, would throw some light upon this subject, and in 

 submitting a paper to the British Association, 1840, I ex- 

 pressed a wish that means might be adopted to test the cor- 

 rectness of the theory, by electrical balloons ; "for if electrical 

 conductors could be raised to the clouds in the frigid regions 

 during the severe frosts of winter, I believe it possible to 

 cause the aurora, and perhaps with startling and extraordinary 

 effects ; and I have no doubt it would lead to very important 

 discoveries in the science of magnetism : to shew the proba- 

 bility of which, I beg to direct attention to the observations of 

 Captain Franklin, who found the aurora had great effect on 

 the needle at Fort-Franklin ; and those of Captain Parry, 

 who found the aurora had no effect whatever at Fort-Bowen. 



" This discrepancy is confirmatory of the theory : for as the 

 magnetic pole is computed to be in 70° 0' north latitude, streams 

 of electricity rushing thence to the equator could not act on 

 the needle at Port-Bo wen, which is in 73° 4' north, but would 

 act on the needle at Fort Franklin, in 65° 12' north.'* 



Notices of Nerc Localities of Bare Minerals^ and Beasons for 

 Uniting several supposed distinct Species. By Francis Al- 

 ger, Member of the Boston Society of Natural History, of 

 the American Academy of Arts and Sciences, &c.* 



Phacolite from New York. — This rare mineral, which comes to 

 us principally from Bohemia and Ireland, I have discovered among 

 a suite of specimens of various kinds found on New York Island, near 

 Harlem, by Messrs Mathews and Johnson, of New York city. The 



Read before the Boston Society of Natural History, January 7, 1846. 



