[ 2 7 + 3 
the given temperature is greater or Iefs than -j- 40 ; 
and that the term — - y is negative when n in the 
denominator of its coefficient is pofitive, and vice 
verfa. Thus the radical number, for the tempera- 
ture o, is 673 1 ,2 
This table is not intended for any practical pur- 
pofes j but merely for fpeculative amufement. They, 
who take delight in the contemplation of final 
caufes, will remark, with admiration, how large a 
part of the whole rarefaction of the atmofphere is 
performed on this fide of the moon. Indeed there is 
comparatively but a very fmail part performed be- 
yond it : fo that the moon revolves at a difiance 
where the refiftance, from the earth’s atmofphere, 
is reduced almod to its minimum . For if we ima- 
gine a feries of quantities, confiding of 101 terms, 
decreafing from the firfl continually in geometrical 
proportion j and fuch, that the fird and greated 
lhall be to the lad and lead, as the denfity of the 
atmofphere, at the earth’s furface, to the denfity at 
an infinite didance ; the denfity, at the mean 
didance of the moon, will be lefs than the 99th of 
thefe, or the lead but two. 
4. An increafe of temperature rarefies the lower 
regions of the atmofphere , tnore in proportion than 
the upper, and brings the conjlitution of the whole 
nearer to that of an uniform denfity. Though the 
effect of heat alone, upon every orb of the atmo- 
fphere feparately, is to rarefy each, perhaps, propor- 
tionally, yet its operation upon the different orbs 
is fo modified, by the different degres of preflure 
they 
