[ I'i ] 



By our prefent imperfefl; knowledge of the phyfiology of 

 plants, we are neceffitated to accept of every affiftance within 

 our reach: and plants being fo immediately connedled with 

 every modification of the atmofphere, meteorology, which has 

 hitherto been confidered as an obje6l of curiofity, is a fource from 

 which we may derive much ufeful information. 



Heat being found to increafe or decreafe nearly in a regular 

 progreffion, according to the degrees of latitude, if the latitude 

 of the place where a plant is found be known, by confulting 

 Mr. Kirwan's Table of the Mean Annual Temperature of 

 different Latitudes*, we may find whether the temperature nearly 

 correfponds with our own. Or, fuppofing the mean annual tem- 

 perature of Dubhn, lat. 52®, equal 50 of temperature, by adding 

 Qne for every degree of latitude fouthward, and fubtradling one for 

 every degree of latitude northward, we have the temperature 

 corredly enough for our purpofe. For thefe calculations need not 

 be carried to the greateft degree of corredriefs, as we know that, 

 if we except a few, plants have a confiderable range of latitude • 

 thofe which cannot bear froft, being found to extend from the 

 northern to the fouthern verge of the torrid zone, and many of 

 thofe which grow on the fouthern limits of the temperate, to ap- 

 proach the borders of the frozen zone. Thus of the Lapland 



Vol. VIII. , P plants, 



* See an Eftimate of the Temperature of Different Latitudes by R. Kirwan, Efq; 

 page 17. 



