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



son, {Louisiana,) Lat. 30° 51 ' 25" N., 



Long 



9 1° 9' W. of 



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

 M. Carpenter, M. D. 



YEARS 



1839. 



1840. 

 1841. 



Months. 



January, 



February, 



March, 

 April, 



May, 



Jane, 



July, 



August, 



September, 



October, 



November, 



December, 



THERMOMETER. 



Mean Temperatures. 





o 





DO 



S 



a 



3 



- 



m 



o* 



45.0 51.5 

 47.2 53.4 

 52.2 64. v 

 62.371.5 

 67.6 75.7 

 74.5 34.5 

 77.5 38.0 

 75.0 S6.5 





70.0 

 63.4 

 48.0 

 46.0 



32.2 

 73.0 

 54.0 

 52.3 



Annual mean, J60.769.7 



c 



3 



m 

 49.0 

 50.0 

 58.0 

 65.5 

 72.4 

 31.3 

 84.0 

 33.3 

 78.0 

 70.0 

 50.0 

 49.5 



U- 3 



£ S 



c P 

 o 2 



48.2 47.047.6 74 



50.3 48.649.474 

 58.2 55.1 

 66.9 63.9 



71.6 70.0 

 79.5 77.9 



82.7 80.7 



80.7 79. 1 

 76.174.0 



68.2 66 7 

 51.0 49.0 

 49.147.7 



BAROMETER. 



30.20 29.50 

 30.15 29.30' 



30.50 29.401.10 



30.12j29.70 

 30.1029.70 



50.07725 





48.4 67118149! 



65.9J65.2 63.3 64.2 



29.89 30.00 29.78 



29.90 30.03 29.78 

 29.83 29.94 29.73 

 29.92129.95 29.90 



9.92J29.94 29.89 

 29.90 30.00 29.80 30.00 29.80 



30.10 29.78 

 30.06 29.82 

 30.05 29 76 

 30.10 29.69 

 30.03 29 70 

 30.20 29.90 



.70 

 .85 



164.330.00 30.02 29.98 

 29.92,29.94 29.9(1 



29.9 1J29.93 29.89 



29.91 [29.95 "29.87 

 29.87 29.89 29.85 

 »D.O0l3O.O5 r 29.96 



9.91 



.42 

 .40 

 .20 

 .32 

 .24 

 .29 

 .41 

 .33 

 .30 



Mean temperature of Jive years, compared with the temperature of well and spring 



water of the same neighborhood. 



Years. 



Mean, 



Annual temper 

 ature. 



Mean temperature of water 

 of wells eighty feet deep. 



64.18 

 64.27 

 64.14 

 64.23 



64.28 



64.24 



Mean temperature of the water 

 of the coldest springs. 



64.25 



64.25 



Vol. xliv, No. 1.— Oct.-Dec. 1842. 



7 



Mo. Bot. Garden. 



