is) 
tention to the thermometer, I found, that the heat 
in tents was remarkable for its degree, fudden and 
great viciflitudes, and alinod continual variation from 
the date of the open air. As a fpecimen of this,, 
and in compliance with your delire, I have fent you 
a table of my obfervations on this fubjedt, during 
our incampment in Dutch Brabant, in the lad year 
of the war. 
It will be proper to obferve, that, to keep the 
thermometers, placed in the open air, from the di- 
red: rays of the fun, it was necelfary to fufpend 
them fo low, that the reflexion of heat from the 
earth mud fometimes have rais’d the Me cury higher,, 
than would have happen’d, had the indruments been 
remov’d farther from the ground ; and it mud alfo 
be remember’d, that, for fome days of this feafon > 
the weather was uncommonly warm. 
In keeping this journal, I obferv’d, 
1. That, in tents, the heat frequently varies 20, 
2f, and fometimes 30 degrees in twenty-four hours; 
reckoning by Fahrenheit’s fcale. 
2. That the uneadnefs, felt upon great changes 
of heat and cold, depends more upon the fudden 
change from the one to the other, than upon the 
excefs of either ; having often feen, in a long courfe 
of fultry weather, men fitting unconcernedly in 
their tents, when the air they breath’d in was rais’d 
to about <?o degrees ; and the fame men in winter 
danding in the open air with no warmer cloathq 
and yet without any complaint, tho’ the cold was 
fome degrees below the freezing point. Whence 
it appears, that, if fuch a change of air be gradual, 
the fame perfon can, without any uneafy fenfatioiq 
bear 
