File:Bell telephone magazine (1922) (14570276067).jpg

Identifier: belltelephonemag19amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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only audible bythose with exceptionally acute hear-ing. The number of pulses heardeach time was recorded in a columnon the card. When the series for thelowest tone had been completed, thetone an octave higher was sounded, atfirst loud and then progressivelyfainter. The complete test showedfive rows of figures on the card, eachcorresponding to a different pitch. On the back of the card was printedin reverse the correct number ofpulses sounded. By holding the cardso that light passed through it, thesenumbers could be seen and they pro-vided a check on the accuracy of thenumbers written down by the visitor.Designations normal or good,slightly impaired and impairedalso showed through the card oppositethe 8th, 5th and 2nd steps respect-ively, to give a qualitative indicationof the hearing acuity. From thesetone-test cards the hearing studieswere made. Before the person tested left theroom, he was asked if he would allowhis record to be photographed for 268 Bell Telephone Quarterly OCTOBER
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TAKING THE TESTS Sound-proof rooms, each containing individual sections such as are shown here, were used at both Worlds Fairs analysis. Permission granted, the at-tendant put a check mark on the cardin code to indicate whether the visitorwas male or female, white or black,and to which of the five age groups10-19, 20-29, 30-39, 40-49 or 50-59he belonged. A photographic record of the cardwas then made on 16-millimeter filmin a Recordak machine, after whichthe card was returned to the persontested. These records were trans-ferred to punch cards later at theLaboratories, by an operator whoviewed the film in a projector. Thepunched cards showed, besides the re-sults of the hearing test at each fre- quency, the age, sex, and the date andhour when the test was made. Thedata were summarized by running thecards through a tabulating machine. Equipment for the Tests io assure that the test tones andthe numbers spoken in the word testwere always the same, they were re-corded on hill and dale dis

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