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The properties of tungsten and the characteristics of tungsten lamps
NELA
RESEARCH
LABORATORY
NOTES.*
THE PROPERTIES OF TUNGSTEN AND THE CHARACTERISTICS OF TUNGSTEN LAMPS. By W. E. Forsythe and A. G. Worthing.
THE results of an extensive study of tungsten, with all the data based on the same temperature scale, are presented under the following subdivisions.
Radiational, Electrical, Thermal, and Mechanical Properties of Tungsten.--For the temperatures for which data are available these properties are shown in figures and tables, for IOO° intervals, for a temperature range from 300 ° K. to the melting point (3655 ° K.). Many interrelations between the properties are pointed out. Characteristics of Tungsten Lamps.--This includes a discussion with data of changes with temperature for ( I ) voltage, current, wattage, candlepower, efficiency, and life of vacuum lamps; (2) dependence of current, voltage, etc., upon filament dimensions; (3) photographic effects, and (4) gas losses. End Losses.--Losses due to heat conduction from a filament to the leads and supports are discussed and methods are given for correcting them. There is given a table showing filament lengths necessary in order that the central portions of different sized filaments, operating at various temperatures, shall be free from effects due to end losses.
Temperature, Brightness, and E~ciency of Some Commercial Larnps.--Tables are given showing data for commercial lamps. The complete paper will be published in an early number of the Astrophysical Journal. A
New
Phenomenon
in
the
Diamagnetism
of
Gases.
A. GLASER. (Ann. d. Physik, No. 21, I924.)--Of all substances gases have been the most difficult to investigate magnetically. This is because of the feebleness of the forces experienced by "them in a magnetic field. Up to about 1919 little more could be foun4 recorded concerning the susceptibility of gases than the positive or negative sign, and this was not always certain. Since the year stated, Tak6 * Communicated by the Director. VOL. I99, No. I I 9 O ~ I 9
RESEARCH
LABORATORY
NOTES.*
THE PROPERTIES OF TUNGSTEN AND THE CHARACTERISTICS OF TUNGSTEN LAMPS. By W. E. Forsythe and A. G. Worthing.
THE results of an extensive study of tungsten, with all the data based on the same temperature scale, are presented under the following subdivisions.
Radiational, Electrical, Thermal, and Mechanical Properties of Tungsten.--For the temperatures for which data are available these properties are shown in figures and tables, for IOO° intervals, for a temperature range from 300 ° K. to the melting point (3655 ° K.). Many interrelations between the properties are pointed out. Characteristics of Tungsten Lamps.--This includes a discussion with data of changes with temperature for ( I ) voltage, current, wattage, candlepower, efficiency, and life of vacuum lamps; (2) dependence of current, voltage, etc., upon filament dimensions; (3) photographic effects, and (4) gas losses. End Losses.--Losses due to heat conduction from a filament to the leads and supports are discussed and methods are given for correcting them. There is given a table showing filament lengths necessary in order that the central portions of different sized filaments, operating at various temperatures, shall be free from effects due to end losses.
Temperature, Brightness, and E~ciency of Some Commercial Larnps.--Tables are given showing data for commercial lamps. The complete paper will be published in an early number of the Astrophysical Journal. A
New
Phenomenon
in
the
Diamagnetism
of
Gases.
A. GLASER. (Ann. d. Physik, No. 21, I924.)--Of all substances gases have been the most difficult to investigate magnetically. This is because of the feebleness of the forces experienced by "them in a magnetic field. Up to about 1919 little more could be foun4 recorded concerning the susceptibility of gases than the positive or negative sign, and this was not always certain. Since the year stated, Tak6 * Communicated by the Director. VOL. I99, No. I I 9 O ~ I 9