Measures for Progress: A History of the National Bureau of Standards

196 THE WAR YEARS (1917-19)
up clear signals transmitted from Germany, from Paris, Rome, and Cali-
fornia. Still later tests proved it possible to transmit as well as receive radio
messages in a submerged submarine, although the sending range, about 12
miles, was shoit84
Experiments with the radio direction finder as an aid in aviation began
in 1918 soon after the Post Office Department started a daily airmail service
between New York and Washington. Night flights of the mail were still 3
years away, 'but presenting an immediate and comparable hazard was the
problem of flying in daytime rain and fog. The pilot's compass guided him
toward his landing field but gave him no indication when he was over it.
At the request of the Post Office, the Bureau took up the problem and made
two adaptations of the direction finder that answered it, one employing
magnetic induction, the other a radiofrequency current. Either of these
enabled the pilot to hear a signal when he was directly over the field. A
crude device and effective only at altitudes up to a mile, it was nevertheless the
forerunner of modern instrument landing techniques.85
No invention factory, the Bureau was drawn into these and other
experiments as the organization best equipped to handle such problems
for other Government agencies.86 In radio research, its mission of pro-
viding and maintaining basic measurements was better exemplified in the
constant and careful reassessments made of its standards of inductance and
capacitance on which standards of radiofrequency or wavelength were based,
84 Work, pp. 229—232.
85 Letter, SWS to Postmaster General, Nov. 29, 1919 (NBS Box 10, JEW); "War Work,"
pp. 232—233; NBS Annual Report 1919, PP. 66—67.
One of the prime functions of the Bureau, the solution of problems relating to measure-
ment, inevitably led to a number of patentable materials, processes, and products.
From about 1910 on, members of the Bureau were granted a steady stream of patents
for new or improved instruments and devices, including a new type of thermopile
by Coblentz (1913), Kolster's decremeter (1913), Schlink's improvements in weighing
scales (1916), Kolster's radio direction finder (1916), Whittemore's element for air-
foils (1918), Willoughby and Lowell's submarine radio (1919), porcelain
for spark plugs (1919), Priest's inferential dilatometer (1919), Ingberg's fire-resistant
column cap (1920), and Emley's pla4tic gypsum (1920). A more complete list appears
in NBS Box 71, AB—2105.
Although other Government agencies permitted and even encouraged their employees
to take out patents in their own names and exploit them, under Stratton it was an
unwritten but inviolable policy of the Bureau that patents of its employees were to be
assigned to the use of the Government and the free use of the public. (Letter, SWS
to Commissioner, Bureau of Navigation, May 21, 1913, and letter, SWS to W. D.
Shoemaker, Patent Office, Aug. 28, 1919, in NBS Box 4, AGP.) No evidence appears
in Bureau records that industry ever objected to this policy, but Bureau inventors
were not always happy with it and on occasion rebelled. See Coblentz, From the
Life of a Researcher (New York: Philosophical Library, 1951), pp. 141—143, and foot
note ch. VI, pp. 348—349.