Correspondence: Polyphase commutator machines

To the Editor: An article under this heading appears in the January issue of the Journal, attributed to myself. In spite of the title the Article itself deals with only one type of frequency changer, and even for that machine only discusses some of the I²R losses, but the broad titles which appears above the article has no doubt arisen by reason of the inclusion, through some inadvertence, of the matter contained in a hastily compiled memorandum dealing with another subject, and not intended for publication; this composes the first five paragraphs and the first (unnumbered) figure of the article in question.