Climate of London and Philadelphia, 15 



The summer of 1804 was considered more cool 

 and temperate than common. My thermometer, in 

 July, placed in the open air, in a north-east aspect, 

 about fifteen feet from the ground, vibrated between 

 80° and 90°, but never stood higher than 91°, though, 

 in other parts of the city, it was said to reach 92°, 

 and at the Federal City 95°. 



In the coldest part of the winter of 1804-5, which 

 was allowed to be uncommonly severe, the thermo- 

 meter varied from 15° to 10°, and finally sunk to 3°, 

 which was the lowest I saw it, though other observers 

 allege it was more than once below zero ; and, in the 

 neighbourhood of Boston, at least 12° lower than at 

 Philadelphia, which, it is presumed, must have been 

 an hour or two before sun-rise. But what are these, 

 when compared with the extremes of heat and cold 

 experienced in many parts of the torrid and frozen 

 zones ? For instance, amidst the burning sands of 

 Nubia, where the thermometer is said to stand at 112° 

 in the shade ; or on the inhospitable coast of Green- 

 land or Spitsbergen, Mhere, in the depth of winter, 

 the natural cold alone is sufficient to freeze mercury. 



A principal cause of the different result of experi- 

 ments, made in the same city, is to be chiefly attri- 

 buted to the bad construction of the instrument, and 

 irregularity of the scale. If, instead of the various 

 thermometers at present employed by different na- 

 tions, they would agree to use one uniform scale, as 

 that of Fahrenheit only, and made by none but able 

 artists, their experiments might then be more accu- 



