INTRODUCTION. tj 



A£ further experience and obfervation fliould con- 

 firm the above opinions, it "will be attended with 

 this advantage, that we fhall be poflefled of a ready 

 method of afcertaining the mean temperature of any 

 climate; which, with a few obfervations of the ex« 

 tremes of heat and cold at particular feafons, will 

 teach us as much of the country, with regard to heat 

 and cold, as the meteorological obfervations of feve- 

 ral years. 



For obtaining the temperature of the earth, the 

 bed obfervations are probably to be colle6i:ed from 

 wells of confiderable depth, and in which there is 

 not much water. Springs iffuing from the earth, 

 although indicating the temperature of the ground 

 from whence they proceed, are not fo much to be 

 depended upon as wells ; for the courfe of the fpring 

 may be derived from high ground in the neighbour- 

 hood, and it will thence be colder : And it may run 

 fo near the furface, as to be liable to variations of 

 heat and cold, from fummer and winter ; or it may 

 be expofed to local caufes of heat in the bowels of 

 the earth. 



Wells feem alfo better than deep caverns; for 

 the apertures to fuch are often large, and may admit 

 enough of the external air to occafion fome change in 

 their temperature. Wells are, however, not to be 

 met with in all places ; and in that cafe, we mud 

 remain fatisfied with the fprings. 



The following obfervations were made in the ifland 

 of Jamaica, where there are flat lands in many part4 

 tow;irds the coaft, but all the interior part of the 



country 



