Hence, omitting the terms which cancel in virtue of Sec. 1 (13), we find

/ dP[Tau]\ / dP[Tau]\

[Sigma]m(x"[delta]x + y"[delta]y + z"[delta]z) = (p`1 - ------- ) [delta]q1 + (p`2 - ------- ) [delta]q2 + ... (6)

\ dPq1 / \ dPq2 /