together with some remarks upon sensible cold, 71 



south and south-west. On the hottest of these days Mr. Ca- 

 vendish's thermometer at Clapham rose to 96°. 



It is true that other accounts have been recorded, some in 

 the Transactions of this Society, of hot days, or hot seasons, 

 which may have equalled, or possibly surpassed this: but 

 till within the last sixty years, the use of the thermometer 

 had hardly been understood sufficiently to enable one to rely 

 upon the vague statements of earlier times. 

 - To persons who may wish to compare this with the heat 

 of tropical countries, it will not be thought superfluous to 

 add, that the late Dr. Hunter, whose accuracy is well-known 

 to many members of the Royal Society, has stated in his 

 valuable account of diseases in the West Indies, that the 

 range of the thermometer at the hottest part of the day, and 

 in the hottest season of the year, at Kingston, in Jamaica, is 

 from 85** to 90®. In the coldest season it is about 5° lower. 



It is not the least singular circumstance attending the heat 

 of last July, that it should have subsided without rain, without 

 lightning, without any change of wind, or any obvious 

 cause ; the succeeding days continuing dry and fair, as those 

 before. 



I am tempted to add to the above some other observations, 

 which, if they are not immediately connected, are not entirely 

 unconnected with this subject; for it cannot have escaped 

 the attention of any person moderately conversant with 

 natural philosophy, that the index of a thermometer is a very 

 imperfect measure of what I may call the sensible cold, that 

 is, of the degree of cold perceptible to the human body in its 

 ordinary exposure to the atmosphere. For while the ther- 

 mometer truly marks the temperature of the medium in 



