Meteorological Register at Jackson, La. 



49 



They are not very dense, having rather a hazy appearance, but 

 are very continuous ; and it rarely rains from them while they 

 retain this form. 



These clouds, as well as the fogs from which they originate, 

 exercise a highly beneficial influence on vegetation ; the former 

 protecting it from the direct heat of the sun, while yet moist 

 from the dew and fog of the preceding night ; and the latter, by 

 putting a check upon nocturnal radiation, thus lessening the fluc- 

 tuations of temperature. 



Jackson, La., May 9, 1842. 



Art. Y. — Abstract of a Meteorological Register, kept at Jack- 

 son, {Louisiana,) Lat. 30° 5V 25" N., Long. 91° 9 / W. of 

 Greenwich, during three years ending Jan. 1, 1842 ; by W. 

 M. Carpenter, M. D. 



Mean temperature of five years, compared with the temperature of xcell and spring 

 water of the same neighborhood. 



Vol. xliv, No. 1.— Oct.-Dec. 1842. 



