LABORS OF THE JOINT COMMITTEE. 83 



In all the great fluctuations of the barometer which oc- 

 curred in January and February, 1835, at Nashville, Tenn., 

 they were one day sooner than at Philadelphia ; and on the 

 22d of March, the barometer was lowest at Philadelphia at 

 three o'clock, P. M. ; whereas, at Providence, R. I., it con- 

 tinued to fall till nine o'clock, P. M., as very particularly 

 noted by professor Caswell. The exact moment of greatest 

 depression at Portsmouth is not given by Mr. Mull, but it 

 was lower there at seven o'clock, P. M., on the 23d, than 

 on the 22d at sunset ; at which time it had already risen 

 more than half an inch at Philadelphia. 



Do these barometric fluctuations of great magnitude travel 

 north eastwardly ? l 



Again, on the 22d of March, at the moment when the 

 barometer was lowest at Philadelphia, the wind at York, 

 Pa., at Flushing, N. Y., at Middletown, Conn., at Provi- 

 dence, R. L, and at Portsmouth, N. H., was blowing 

 towards Philadelphia violently, especially at York and 

 Portsmouth, while at Philadelphia it was a perfect calm. 

 There was also, on that day, a very violent rain at York, 

 and in Berks county, Pa., and at Baltimore, and also a con- 

 siderable rain at Flushing, Middletown, and Providence, at 

 the same time, when there was a calm in Philadelphia, and 

 no rain ; and as this state of things continued for many 

 hours, it seems probable that the air, which moved with 

 great rapidity towards Philadelphia, in opposite directions, 

 must have ascended over Philadelphia, and passed off above 

 even with greater rapidity than it approached below, or 

 otherwise the barometer must have risen, in a very short 

 time, to a great height, by the conflicting impulse of these 

 two opposite currents ; but the barometer stood all this 

 time more than three quarters of an inch lower than usual. 



1 Many facts have come to my knowledge since, that lead me to believe 

 that barometric fluctuations, of great magnitude and extent, travel towards a 

 point a little south of east. AUTHOR. 



