12 



servations at Toronto and Philadelphia, by Lieut. Lefroy and Prof. 

 Bache. Other comparisons will probably be had through the obser- 

 vations at Montreal and Quebec. 



Professor Bache expressed the hope that the magnetic survey of 

 the State of New York, would not be left to the desultory efforts of 

 individuals, but would be undertaken and rendered systematic and 

 complete, by the authorities of the State. 



Professor Frazer made some remarks on the tornado of Aug. 

 Sth, and exhibited a specimen of earth, apparently silicious, 

 which was deposited by it in considerable quantity, within the 

 chimneys of a house over which it passed in Delaware county, 

 and which he regarded as bearing on the question whether the 

 rain proceeded from a water-spout. Prof. F. had traced the 

 line, which formed the eastern limit of the tornado, and found 

 it to be a curve: the western line he had been unable to de- 

 fine. He remarked, that where its path lay through a wood, 

 the large trees were generally prostrated, while the small ones 

 escaped. 



A similar remark had been made by Professor Bache as to 

 the comparative destruction of the larger and smaller trees in 

 the paths of several tornadoes which he had witnessed: and it 

 was observed by Mr. Hassler, that it was of universal occur- 

 rence, and was referrible to the fact that the roots of young 

 trees penetrate more deeply into the ground than those of older 

 ones, and are besides proportionably larger. 



The phenomena presented by the tornado of August had 

 been observed in different places by others of the members. 

 The minimum of rain, which was marked as having fallen 

 within its range, was ten inches. The district over which it 

 passed was very limited, but its path was such as to cover the 

 entire course of the principal streams of Delaware county. 

 This circumstance was adverted to as explaining the desolating 

 height to which the waters were raised. 



Mr. Kane, Reporter, announced that the Discourse of Dr. 

 Patterson at the Centennial Celebration, with the proceedings 

 by which it was introduced, had been printed, and was now 

 ready for distribution. He mentioned that the Proceedings of 

 the Centennary Meeting of the Society would be in print be- 

 fore the next meeting. 



