ic6 Mr. Six's Experiments 
Being defirous of knowing whether the no£lurnal refrigera- 
tion increafed on a nearer approach to the furface of the earth* 
I placed, in the midfl of an open meadow, on the bank of the 
river, near this city, two thermometers ; one on the ground, 
and the other fix feet above it ; with thefe, and the two others 
before mentioned, one on the tower, and the other in my 
garden, I made obfervations from the ioth to the 23d of Ofto- 
ber, 1786. See Tab. III. But as the thermometer fix feet 
from the ground, in the meadow, nearly agreed with that in the 
garden at nine feet, I have omitted an account of the latter ill’ 
this table of companion. Here I found, as before, the noc- 
turnal variations entirely regulated by the clearnefs, or the- 
clondinefs, of the Iky ; and although they did not always 
happen in the fame proportion to the refpedlive altitudes, yet, 
when the thermometers differed at all, that on the ground was 
always the coldefl. 
Finding fo confiderable a difference as three degrees and a 
half, within fix feet of the earth’s furface, I increafed the 
1 
number of my thermometers in the meadow to four ; one of 
them I funk in the ground, another I placed juft upon the 
ground, a third I fufpended at three feet, and a fourth at fix 
feet from the ground ; at the fame time I placed three thermo- 
meters in an open garden on St. Thomas’s Hill, where the 
land is level with the Cathedral Tower, and about a mile 
diftant from it ; here I likewife put one in the ground, ano- 
ther juft upon it, and fufpended a third fix feet above it. 
tables of comparifon. It is true, when the weather was clear and not too cold, 
the upper ones indicated drynefs more than the lower; but in frolly weather, the 
contraction and expanfion of the hygrometers being impeded by the froil, they did 
wot in any regular manner agree with the variations of the thermometer. 
With 
