8 THE AMERICAN STORM OF DECEMBER 20, 1836. 



evenino- of the 21st the storm is confined to the eastern margin of the churt, while 

 the western boundary of the rain has passed to the cast side of the Connecticut 

 river; and throughout the whole of the United States, except New England and 

 two or three small spots of limited extent, the sky is entirely free from clouds. 



Throughout the entire United States the average amount of rain which fell 

 duriuf this storm was seven-eighths of an inch, and although the fall at different 

 places Avas very unequal, still the average amount was sensibly the same on the 

 eastern as on the western part of the country, and on the north side nearly equal 

 to that on the south side. 



Direction of the Wind. 



On the accompanying charts the direction of the Avind has been indicated by 

 arrows, according to the observations given in my first memoir, pp. 137-139. It 

 will be seen that on the evening of the 19th, throughout the area of rain and snow 

 as far as it is exhibited on the chart, the wind blew from the south or southeast. 

 On the east side of the boundary of rain and snow, but within the limits of the 

 cloud, the winds appear to be somewhat influenced by the storm ; but in New 

 England the winds blow from about their normal direction ; that is, from the west, 

 inclining somewhat to the northwest. 



On the morning of the 20th, beyond the Mississippi river, the winds had changed 

 to the north and northwest ; but on the eastern half of the area of rain and snow 

 the prevalent direction of the winds was from the southeast. For some distance 

 beyond the boundary of the rain on the east, the Avinds inclined towards the south- 

 east, while along the northeast border of the United States the winds were gene- 

 rally from the southwest; but they were light, and in some places changing to 

 northeast. 



On the evening of the 20th, beyond the meridian of Chicago, the winds every- 

 where blew from the north or northwest. Throughout all the remaining part of 

 the United States, Avith here and there a solitary exception, the winds blcAv from 

 some southern quarter, and the prevalent direction Avas from a point a foAV degrees 

 cast of south. 



On the morning of the 21st, on the Avest side of the centre of the storm, the 

 Avinds were generally from the Avest and nortliAvest ; the prevalent direction being 

 from a point a fcAv degrees north of Avest. On the east side of the centre of the 

 storm, the Avinds Avere generally from the south and southeast, the pi'CA'alent direc- 

 tion being from a point a little east of south. 



On the evening of the 21st, througliout the extreme western part of the United 

 (States, the winds were becoming less northerly than in the morning ; but in the 

 neighborhood of the storm, on the Avest side of its centre, the Avinds continue from 

 the Avest and nortliAvest ; the prevalent direction being about thirty degrees north 

 of Avest ; while on the east side of the centre the Avinds are from the south and 

 southeast. 



It Avill thus be seen that during the entire period in question, Avithin the area 

 of rain and snow, the direction of the Avinds was quite imiform. In the rear of the 



