Digest of United States Patents Relating to Radio Telegraphy and Telephony: Issued April 19, 1921-June 14, 1921

The object of this section in the Proceedings of the Institute of Radio Engineers is to make available in convenient form for research engineers and others interested, brief information on radio patents which are issued each week by the Patent Office. The rapid development in this art emphasizes the importance of radio research engineers being familiar with patent literature to eliminate, as far as possible, the duplication of effort in research. It is not the purpose of this section to explain radio inventions fully, but merely to indicate the general nature of the patents in order that those of particular interest to individuals concerned with certain problems may be selected and complete copies of the patents obtained for study. Copies of the patents may be secured at ten cents each by communicating with the Commissioner of Patents, Washington, DC.