[ *77 ] 
the - cooler condition of the air, and^>0, jGH as the' 
denfities at the fame heights P and B,. in the in- 
ereafed temperature, p O is lefs than to bear to /SH, 
the proportion of p N to jQE (by 4th of this) : 
and, by permutation, pO is lefs than to bear to/>N 
the proportion of /3H to /3E, or of /3L to /3 M- 
Therefore p O x 13 M is lefs than/>Nx/3L$ that is, 
the area intercepted between the ordinate p O, the 
curve OHK,and the alymptote pC infinitely pro- 
duced, is lefs than the area intercepted by the ordi- 
nate p N, the curve NEF, and the afymptote pQ. 
infinitely produced. But again, thefe areas are 
as the prefiures of all the atmofphere above P, in> 
the temperatures to which: the curves refpectively 
belong j therefore, the prefiures in the greater tem- 
perature, to which the ‘turv.e O HK belongs, is lefs. 
than the prefiure in the cooler temperature, to which 
NEF belongs, ijh E. D. In like manner it may 
be (hewn, that the prefiures in the warmer tempe- 
rature, at all heights above B, are greater than in. 
the cooler. 
And thus theory might have brought us to ex- 
pert a phaenomenon, which M. de luc hath actually 
obferved, and was not a little furprifed at.. For if 
the temperature of the atmofphere be at any time 
gradually augmented, a barometer, placed below the 
height of ftationary prefiure,, will fink, while ano- 
ther, placed higher up in the atmoiphere, will rife,. 
This is what M. de luc hath obferved in two ba- 
rometers at the foot and fummit of a hill, in fettled, 
weather, while the natural heat of the day hath, 
been upon the increafe;. from whence he, with. 
reafon,, 
