Oi) REPORT OF THE SECRETARY. 



form of an oval figure, having a length of three times its breadth, 

 and, from the inspection of the several maps', it will appear that it 

 travelled constantly eastward. 



A similar table of observations is given in reference to the ther- 

 mometer as observed at fifty-seven places, and lines corresponding 

 to the mean temperature to ten degrees above and ten degrees below, 

 &c., are drawn on each of the maps. From these it appears that on 

 the evening of the 19th the area of greatest temperature extended 



m 800 to 1.100 miles in an east and west direction. The centre 

 of this area of high thermometer did not coincide with the centre of 

 low barometer, but was uniformly somewhat to the east of it. 



On the same charts the condition of the weather at different inter- 

 vals as to clearness, cloudiness, rain, &c., is represented by different 

 colors, and from these it will be seen that on the evening of* the 19th 

 of December rain or snow was falling over the entire region west of 

 the Mississippi as far as the map extends, and that a cloud covered 

 the whole of the United States except that part bordering on the 

 Atlantic ocean. On the evening of the 20th the rain had reached 

 Washington, and on the morning of the 21st the cloud had covered 

 the whole of the eastern portion of the country, while the sky had 

 cleared off as far as Cincinnati, at the same time that rain was falling 

 in the whole of New England except the State of Maine. On the 

 evening of the 21st the storm was confined to a small portion of the 

 eastern part of the chart, while the sky over nearly the whole United 

 States, with a few exceptions of spots of limited extent, was free from 

 clouds. 



The direction of the wind is indicated by arrows, and its intensity 

 shown by their length; and from these it is seen that during the en- 

 tire period within the area of rain and snow the direction of the wind 

 in the rear of the storm was from the west, northwest, or north, and 

 that in the southwest part of the United States the winds were some- 

 what more northerly than in the northwest part of the country. In 

 front of the storm the winds generally blew from a southerly point, 

 the average of which was 10° east of south, while in the south and 

 northern parts of the country in front of the storm the wind was 

 easterly. There was thus along a meridian line of at least 1,200 

 miles in length a violent wind from a point on an average 30° north 

 of west, and on the east side a strong current from a point 10° east 

 of south. These two contrary winds blew with great violence for at 



