Remarks on the Formation of Fogs. 



43 



Date of observations. 



1842, 



1841, 



(( 



1840, 



u 



1841, 



a 



H 



a 



1842, 



1841, 



Jan'ry 11, 



Feb'y 15, 

 " 25, 



March 27, 

 " 29, 



April 1, 

 " 2, 

 « 5, 

 " 19, 

 " 13, 

 " 27, 

 28, 



3, 



« 5, 



" 13, 



" 16, 



June 19, 



May 





10 A. M. 



10 A. M. 



11 A. M. 

 3 P. M. 

 11 A. M. 



Night. 



3 P. M. 



Night. 



10 A. M. 



11 A. M. 



9 A. M. 



Night. 

 Night. 



11 A. M. 



Night. 



2 P.M. 



10 A. M. 



Ill one of the cases referred to in this table, the opportunities 

 for making the observations were so favorable, the results so sat- 

 isfactory, and the nature and variety of the phenomena so char- 

 acteristic of the particular kind of fogs, that I will give a detailed 

 account of the observations. 



On the 27th of March, 1840, I was at the house of a friend, 

 who lives on the bank of the Mississippi River. The weather 

 was cloudy and rather cool for the season in this climate, the 

 thermometer ranging from 55° to 65° Fahr., though it had ranged 

 during some time previous at from 65° to 75°. The house was 

 situated on the eastern bank, at the distance of about four hun- 

 dred yards from the water's edge, the greater part of the distance 

 intervening being a level plain, elevated at the time of observa- 

 tion only a few feet above the level of the water, then at a high 

 stage ; but near the house the land rises abruptly, forming a bluff 

 about fifty or sixty feet in height, and on this bluff, near the de- 

 clivity, the house is situated. 



About noon there was a light shower of rain, and it remained 

 cloudy during the remainder of the day. At 3 o'clock, p. m., 

 being on the gallery, which commanded a view of the river, I 



