Chem., 1832, 3, p. 2 49) is to be regarded as a most important contribution to the radical theory, for it was shown that a radical containing the elements carbon, hydrogen and oxygen, which they named benzoyl (the termination yl coming from the Gr.
Moreover, instead of having one pair of variables x i, x2 we may have several pairs yl, y2; z i, z2;...