PROFESSOR LOOMIS'S STORM. . 285 



Professor Loomis says in regard to this table : " It will be 

 observed that the range of the barometer increases generally 

 with the latitude." This is one circumstance which ren- 

 ders it highly probable that the storm extended to a great 

 distance farther north than the most northern observations. 

 Another circumstance which favors this conclusion, and in- 

 deed renders it almost certain, is, that the wind every where 

 changed round by the south to west and north west, as the 

 storrn passed on. 



Professor Loomis thinks this storm moved towards the east. 

 The barometric minimum, however, travelled from the W. N. 

 W. to the E. S. E. and it is therefore highly probable, that 

 the storm itself travelled in the same direction. Its velocity 

 of motion in the middle States was about 25 or 30 miles an 

 hour, for it moved from Springfield, Ohio, to Washington 

 City in twelve hours, and to Philadelphia in fourteen hours. 



Its motion seems to have been slower when it reached the 

 British dominions, for it was twenty hours in passing from 

 Quebec to Halifax, a distance of only about 400 miles. The 

 mean velocity from W. N. W. to E. S. E. was not greater 

 than 25 miles ; and as the velocity of the N. W. wind was 

 certainly not less than forty miles, from the manner in which 

 it is generally characterized " violent gale, 3 ' &c. it follows 

 that much of this N. W. current rose on meeting the S. E. 

 current in the middle of the storm ; for if none of it had 

 ascended, the storm would have moved towards the S. E. 

 at least forty miles an hour. Professor Loomis's view, there- 

 fore, that the N. W. wind flowed under the S. PI, is not en- 

 tirely correct ; for about one fourth as much of the N. W. 

 current ascended as of theS. E., and on ascending it would 

 spread outwards above from the expansion produced by the 

 latent heat evolved during the formation of cloud; but it 

 would be driven chiefly towards the eastward, or north east- 

 ward by the upper current of the atmosphere, which moves 

 over the United States generally in that direction. 



