[ 26 ] 
III. The terms F, x, therefore, muft involve a 
common fador; by which being divided, the quote 
jy | 
may be -jr-. And this might be obtained innu- 
merable ways, were we to confider the ratio - 
merely as an abftrad quantity, altogether unreftrid- 
ed : it were only putting M x Qj_ — F. And 
Q* +f> 
M 7 -” 
1 — 
— x, or M rr F, and 
M ” 
— x: fo 
as the fum of the indices of M fhould be unity, and 
the difference of thofe of Q lliould be z. 
But though the quantities F, x, are as yet un- 
known, they are not for that indeterminate and va- 
riable, as fuch a liberty of fubftitution would import : 
and all fubftitutions which imply the contrary, all 
indices which the theory difowns, or which are in- 
confiflent with obfervation, are to be rejeded. In a 
word, the indices , n, p> ought each of them to be 
unique , and determinate (fine compare J, * as the 
quantities F and x are in nature. I take, there- 
fore, p — i, and n = 4. ; that is, F-Ml x Q, 
.v — ^7. See the examples in the table fubjoined, 
upon different fuppolitions of the moon’s diffance.. 
* Sec Neut. A rit h. Univerfal. in the Schol. to Prob. xxiv. 
The maxima and minima of variable quantities ; the coordinates 
belonging to a double point, or to a point of reflexion, or con- 
trary flexure, rays of curvature, limits of ratios, &c. All thefe 
are examples of the unique ; that is, of quantities in a ftate 
that is diftinguifhed from and exclufive of all others. 
IV. The 
I 
