V 2 7S ] 
they fuftain, and by the communication between 
them, that the greater the temperature of the 
atmofphere, though uniform throughout, the lefs 
will the proportion be of the denfity at any 
given height to the denlity at any greater given 
height. For the greater the temperature, the greater 
the fubtangent ; and the greater the fubtangent, the 
lefs the proportion of AD to CF, of which the 
given line AC is the logarithm. ( 'Vid . fig. i.) 
5. If at any height above the fur face of the earth 
a given alteration of temperature diminif the airs 
denfity in the fame proportion, as it increafes the abfohtte 
elaf icity , or vice vexia, the preffure of the fuperin- 
cumbent atmofphere ,. at that height, will remain 
unchanged. At all lower heights , the preffure will 
be lefs, than in a cooler condition of the atmofphere , 
and greater at all greater heights. On the contrary , 
the preffure at all lower heights will be greater than 
in a warmer condition , and at all greater heights lefs. 
For let CA (fig. 2.) reprelent the lemi-diameter of the 
earth, the curve DEF the atmofpherical logarithmic 
for a certain temperature, and G H K the loga- 
rithmic for -another greater temperature. Let the 
ordinates of the two curves AD, AG be as the denfi-- 
ties, at the earth’s furface, in the different tempera- 
tures, to which the curves belong, refpedively. Thera 
it is evident, the ordinates jGE, /3H, drawn through 
any other point /3 in the afymptote, will be as the 
denfities, at the height to which A/3 eorrefponds, in 
the different temperatures, refpe&ively. Now, fup- 
pofe that the denfity of the air, at the height B* 
in. the greater temperature, is lefs than the denfity at 
N n 2 the 
