Abstracts of Technical Articles from Bell System Sources (01 October 1929)

Two reciprocal theorems, the generalized Rayleigh theorem and the Sommerfeld-Pfrang theorem, are of great theoretical importance in radio communication. A careful analysis of these theorems and their mathematical derivations shows that they are quite distinct and their practical fields of application different. In particular it shows that the Sommerfeld-Pfrang theorem labors under restrictions, implicit in its mathematical derivation, which seriously limit its field of practical applicability.