210 NINTH ANNUAL REPORT OF 



I find no traces of accumulation of air in Florida, where the curves ot 

 pressure and moisture coincide very accurately, as much so as they do 

 throughout the Mississippi valley. The following reductions exhibit the 

 state of the barometer over three sections of the United States. The 

 figures show the difference of the pressure above or below the mean 

 for the month, in hundredths of an inch: 



First Section. 



Maine at 7 a. m -\- .23 inches. 



Vermont " " + .21 " 



New York (State) . " " -f- .33 " 



Michigan " '' + .16 •' 



Wisconsin " " + .21 



Second Section. 



North Carolina. ... at 7 a. m mean. 



Kentucky " " — .17 inches. 



Missouri " " -|- .12 " 



Third Section. 



East Florida at 7 a. m — .18 inches. 



Alabama " " — .17 " 



Texas " " + .41 " 



During the weather from the 7th to the 16th of November, the fiucta- 

 ations of the barometer in the southern and western States do not seem 

 to have been greater than could be ascribed to the changes of tempera- 

 lure. The great fall of the barometer in tropical storms, and the torna- 

 does of the United States, seem to me to admit of no other explanation 

 than that given by Professor Espy, viz: an inward ascending column 

 of air becoming much lighter from the extrication of latent caloric. 



In regard to the winds, during the progress of this storm, only two 

 systems are well developed. The northwest w^inds, on the 10th, 

 were observed both in the rear and front, while the southwest current 

 occupied the middle. The east wind is so partially developed, that we 

 must regard it merely as an eddy in the more general system which 

 embraces it. We cannot expect to find much regularity in the course 

 of any set of winds, because this can only take place with an invariable 

 temperature. Inequality of local temperature is the principal cause of 

 the irregularity of the arrows which represent the direction of the wind 

 on the meteorological chart. 



On the 12th, the weather was very wet and stormy along the Atlan- 

 tic States, and much rain also fell in the Ohio valley. Snow fell over 

 a considerable area immediately to the south of the lakes. 



We shall now ver}^ briefiy trace the peculiarities of the weather and 

 storms of Europe. The east w'ind very seldom blows over a large 

 area of the United States, unless during storms. In northern Europe 

 the case is ver}" different: dry and cold \vinds are very common in 

 spring, and, at this season, not only is the surface wind Irom the east, 

 but the current in the higher regions is also fiom the same quarter. It 

 usually bears cirrous clouds, thus showing the great height to which it 

 extends in the atmosj^here. So long as the east w^ind blows as an 



