[ 2 8 7 ] 
an alteration of the quantity of matter in the atmo - 
fphere ; for without this, it cannot be every where 
rarefied, or every where condenfed at one and the 
fame time. 
9 . Having found the heights where the' den fit y is 
the fame in any two different temperatures , the height 
where the prejjures in different temperatures are equal, 
will eafily be determined. For this purpole, we have 
only to feek the folution of the following problem.. 
problem ir. 
1 
Two logarithmics (DQF, GQK) interfering in a 
given point (Q), (fid. fig. 2 .), having a right line 
(AC) given in poftion for their common afymptote , and 
fubtangents feverally given in magnitude ; to fnd the 
point (/3) in the afymptote , where an ordinate (/3HE) 
being drawn at right angles , to meet both curves „ 
the areas intercepted between the two curves and the- 
common afymptote infinitely extended , beyond the ordinate 
/3E, are equal. 
L ET /3L, / 3 M be equal to the fubtangents of 
the curves DQF, GQK, refpedively. Becaufe 
the curvilinear areas are equal 5 therefore, the re£tan~ 
gles /3Lx/3E, /3H x /3M, are equal. Therefore,, 
(3E : (3Hz=(3M : /3L. But / 3 M, /3L, being given,, 
the proportion of (3M to /3L is given. Therefore, 
the proportion of / 3 E to (3H is given. Therefore, 
the point (3 is given (by corollary of preceeding pro- 
blem). 
CON^* 
