the 



AMERICAN 



JOURNAL OF SCIENCE, &c. 



Art. I. — Researches in Elucidation of the Distribution of Heat 

 over the Globe y and especially of the Climatic Features pecu- » 

 har to the Region of the United States ; by Samuel Forry, 

 M. D., Author of "The Climate of the United States and its 

 Endemic Influences," Editor of " The New York Journal of 

 Medicine and the Collateral Sciences," etc. 



(Concluded from p. 50.) 



Another important subject is the influence of temperature on 

 l " e geography of plants, which has been ably treated by M. de 

 ^andolle. In considering its relation with the organic life of 

 plants, it is necessary to keep in view three objects : — 1. The 

 jtoan temperature of the year; 2. The extreme of temperature 

 b °th in regard to heat and cold ; 3. The distribution of tempera- 

 ture among the different months of the year. The last is the 

 most important ; but in the investigation of vegetable geography 

 11 js requisite to estimate the simultaneous influence of all physi- 



causes, — soil, heat, light and the state of the atmosphere as 

 ^gards its humidity, serenity, and variable pressure. Each plant 



and 



cal 



, «.„*,. jr, ociouuji, www . — ™~~ r 



, s generally a particular climate in which it thrives best, 



e yond certain limits it ceases to exist. Hence having seen the 



§ r eat variations of summer and winter temperature on the same 



^thermal line, the absurdity of limiting a vegetable production 



a certain latitude or mean annual temperature, is apparent. 



° sa y that the vine, the olive, and the coffee-tree require, in or- 



* t0 be productive, annual temperatures of 53°-60, 60°-80 and 



01 ^v„, No. 2.-J u ! y _s ( p t. 1844, 39 



