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XXI. An Account of the Meteorological Inflruments ufed 
at the Royal Society’s Houfe . By the Hon. Henry Ca~ 
vendifh, F. R. S. 
R. March 14, 1776. 
Of the thermometers , with reflexions concerning fome pre- 
cautions neceffary to be ufed in making experiments with 
thofe inflruments , and in adjufting their fixed points. 
r | ^ HE thermometers are both adjofted to fahren- 
A heit’s fcale: that without doors is placed out of a 
two-pair-of-ftairs window, looking to the North, and 
Rands about two or three inches from the wall, that it 
may be the more expofed to the air, and the lefs afiedled by 
the heat and cold of the houfe. The fituation is tolerably 
airy, as neither the buildings oppoRte to it, nor thofe on 
each fide, are elevated above it in an angle of more than 
1 2 0 ; but as the oppoRte building is only twenty-five feet 
difiant, perhaps the heat may be a little inereafed at the 
time of the afternoon obfervation by the reflexion from 
thence. In the middle of fummer the Sun fliines on the 
wall of the houfe, againfi which the thermometer is fixed,, 
for an hour or two before the morning obfervation, but 
never 
