*4 
Mr. Ivory on the Method of computing 
i— 1 * + — 
17 
•/f - ( 1 + t)M* •/ 7C= + g -/ t? + &<• } • 
This expression being farther reduced into a series of simple 
terms, those terms will be included either in the form 
whatever number i 
” or j n the form Sr . f- 
fil -4- I U' 
j a - f 1 " 
may denote, the first sort of terms, when they are integrated 
between the proper limits, will be found, on examination, to 
contain a part which, depending only on the nature of the 
molecules or of the function that expresses the thickness of 
the molecules, remains of the same magnitude for all values 
of Sr; and consequently those terms do not necessarily vanish 
when Sr = o : with respect to the second kind of terms, they 
are to be regarded as quantities of the same order with the 
multipliers written without the sign of integration, and they 
all vanish together with Sr. Reserving till afterwards the 
proof of what has now been said, it is sufficient at present 
to have marked, distinctly the characters of the quantities to 
be retained, and of those to be rejected. If then we retain 
the first sort of terms only and reject the rest, the value of 
m ^j^dm 
- — ~ — JP ~ — “ will be equal to the series, viz. 
3 pdm j pbr . dm 3.3 . dm 
-J ’J " 24 'J ~f r ~~ ~ 1 : 
and, by substituting this in the equation (B), we shall get 
(£)=-? 
in which expression the value of all the terras under the sign 
of integration are to be taken on the supposition of Sr = o. 
Finally if, in this last value of |~J and the value of V already 
