"Hence if y be the Root of any Expression formed of y and known Quantities, and supposed equal to nothing, and z be a part of y, and x be formed of z and the known Quantities, in the same manner as the Expression made equal to nothing is formed of y; and let y be equal to z + v; the difference v will be found by Extracting the Root of this expression x + \frac {\dot{x}v}{1} + \frac {\ddot{x} v^2}{1 \cdot 2} + ... etc. = 0."