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Photoelectric ray to determine flying ceiling. Washington, D.C., June 15. To permit a ground observer to determine at what height flying is safe during days of fog and heavy overcast, Miss Elizabeth M. Zandonini, of the Radio Section staff of the Bureau of Standards, is shown with the balloon transmitting equipment. A photoelectric cell measuring light brightness is used to control the pitch of the radio signal transmitted from the balloon as it ascends. A graphical frequency recorder plots the pitch and hence ... a measure of the light brightness as a function ... height. The experiments are carried on for the U.S. ...

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Photoelectric ray to determine flying ceiling. Washington, D.C., June 15. To permit a ground observer to determine at what height flying is safe during days of fog and heavy overcast, Miss Elizabeth M. Zandonini, of the Radio Section staff of the Bureau of Standards, is shown with the balloon transmitting equipment. A photoelectric cell measuring light brightness is used to control the pitch of the radio signal transmitted from the balloon as it ascends. A graphical frequency recorder plots the pitch and hence ... a measure of the light brightness as a function ... height. The experiments are carried on for the U.S. ...

description

Summary

A black and white photo of a woman putting something in a box, Library of Congress Harris and Ewing collection

Title from unverified caption data received with the Harris & Ewing Collection.
Date based on date of negatives in same range.
Gift; Harris & Ewing, Inc. 1955.
General information about the Harris & Ewing Collection is available at http://hdl.loc.gov/loc.pnp/pp.hec
Temp. note: Batch six.

The Harris & Ewing, Inc. Collection of photographic negatives includes glass and film negatives taken by Harris & Ewing, Inc., which provide excellent coverage of Washington people, events, and architecture, during the period 1905-1945. Harris & Ewing, Inc., gave its collection of negatives to the Library in 1955. The Library retained about 50,000 news photographs and 20,000 studio portraits of notable people. Approximately 28,000 negatives have been processed and are available online. (About 42,000 negatives still need to be indexed.)

date_range

Date

01/01/1938
place

Location

district of columbia
create

Source

Library of Congress
copyright

Copyright info

No known restrictions on publication. For more information, see Harris & Ewing Photographs - Rights and Restrictions Information http://www.loc.gov/rr/print/res/140_harr.html

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