242 Of the SOLIDS 
AK ora’, we have the whole attraétion of the folid, or F = 
B4+Ne+a y No + a" 
NG-a  B+Ne+a" 
b4+NC4+a - Vea ( 
Ve + a" b+Vcipa" 
2a—2a —b Log 
— p Log 
Ir, in this value of F, we invert the ratios, in order to make 
the logarithms affirmative, and write like quantities, one under 
the other, we have F= 7a — 7a’ 
G+-VE +a" _ Ve+a 
6L Ss a = SSS 
i 0g B+%o4+a x VO +a“ 
b+No+a*, NB +a 
b4+NG4a ve pa 
+ @ Log 
Tue firft two terms of this expreflion deferve particular at- 
tention, as is an arch, fuch that fin, = fin BAE x fin BAC; 
therefore, by what has been before demonftrated, 4 is the mea- 
fure of the angular {pace fubtended at A by the rectangle BD. 
The firft term in the value of F, therefore, is the product of the 
diftance AB, into the angular fpace fubtended by the rec- 
tangle BD. In like manner, the fecond term, or 7a’, is the 
product of the diftance AK, into the angular {pace fubtended by 
the rectangle KF. 
Tue relation of the quantities exprefling the ratios, in the 
two logarithmic terms, will be beft conceived by fubftitu- — 
ting for the algebraic quantities the lines that correfpond 
to them in the diagram. Becaufe ci = J°+ = EB* + 
BC 
