Mr Johnston's Remarks on Mr Potters Paper. J>fi5 



Lewiston. There appeared two ranges in the north, one above 

 the other, and though irregular, yet in their main direction, 

 parallel, and resembling two sublime ranges of mountains with 

 dark sides and slight summits of immense height, from which 

 the brilliant coruscations, were, by the imagination, easily con- 

 verted into volcanoes. In the horizon, the light extended 

 from the south-east, almost to the west, and the currents and 

 flashes of light rose from the north horizon to the zenith and 

 thence descended half way to the south horizon: Lowville 

 North-Salem, Pittsburgh, Rochester. Very brilliant: St 

 Lawrence, Union, Utica. 



Dec. 12, very brilliant, Auburn. Do. Dutchess, Franklin, 

 Fredonia. Do. Ithaca, Lansingburgh, Lewiston, Middlebury, 

 North-Salem, Plattsburgh, Pompey, St Lawrence, Utica. 



This year has been remarkable for the frequency and often 

 the brilliancy of the Aurora Borealis. In every instance, so 

 far as observations have been made at this place, the phenome- 

 non has presented a dark, dense, and regularly defined cloud 

 lying in the northern horizon, and extending far to the east 

 and west, apparently a ground-work from which the light pro- 

 ceeds. On some evenings this cloud is above the horizon at 

 the first appearance of the flashes of light ; in others it is not 

 visible until after the light has been observed for some hours, 

 and when the flashes have continued late in the night, the 

 cloud ascends above the horizon and the brilliancy of the light 

 diminishes. In one instance, on the evening of the 11th of 

 December, after the cloud had risen ten or fifteen deer-ees 

 above a clear horizon, a second cloud appeared, from which 

 the flashes of light were distinctly seen shooting to the upper 

 one : Utica. 



A et. X I II. — Remarks on Mr Potter s Papt r " on the Specific 

 heats of Metals:'' Py James F. W. Johnston, A. M. &c. 

 &c. Communicated by the Author. 



Bince the admirable experiments of Messrs Dulong and Petit 

 published in the An. de C/ilm. for IS1<), it has been rendered 

 extremely probable " that the atoms of all simple bodies have 



