March 1944 Radio-Craft
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
Probably the biggest news in the
March 1944 issue of Radio-Craft magazine's "Monthly Review" feature was the invention
of an extremely sensitive particle mass analyzer by
Dr. James Hillier,
of Radio Corporation of America (RCA).
who you might recognize as a television pioneer, is in the photo with Dr. Hillier.
A related technology, electron microscopy, was used to image viruses in the blood
National Bureau of Standards, now called
NIST, announced a new time
standard broadcast signal consisting of a precise 2.5 MHz pulsed tone feature
a missing pulse once per minute. This facilitated calibration of frequency and time
standards. There is also an analog simulator built by Westinghouse for use in designing
high voltage power transmission networks where up to 18 separate sources can be
tied into common distribution systems. It eliminated massive amounts of numerical
calculations previous required.
Radio-Electronics Monthly Review
Just a section of the big calculating board.
Cut-And-Try has been carried to
its ultimate in the new and improved A.C. calculating board recently installed by
Westinghouse at East Pittsburgh, according to a report from that company last month.
Every experimenter knows how often, when constructing a new piece of apparatus,
laborious calculations can be saved by setting up a trial job, taking voltage and
current measurements, then making the necessary adjustments.
Westinghouse engineers, faced with highly complicated power circuits, do not
attempt to go through the time-consuming process of mathematical calculations to
learn the conditions in these circuits. Instead, with the new board, they can set
up a "model" of the circuits, with the voltages, currents and phase angles of a
number of voltage sources absolutely measurable, and the possibility of creating
artificial distribution networks of known resistance, inductance and capacity. The
new calculating board thus makes it possible to solve complicated power-system problems
much more readily than on previous calculators. Simulating a total of 18 power sources,
it can be electrically divided in any desired manner for the simultaneous solution
of two small problems or can be operated as a single unit for a large-system study.
Dial-type switching for resistor-reactor circuits facilitates setting and checking
of network impedances. Generator units have independent voltage and phase-angle
controls that simplify adjustments. Instruments have scales that are, read directly
in power-system quantities instead of requiring the application of multipliers,
Two Changes beginning February 1, 1944, were announced in the
standard frequency broadcast service of the National Bureau of Standards. One is
the addition of a new radio frequency, 2500 kilocycles per second at night. The
other is omission of the pulse on the 59th second of every minute. The entire service
is described here. It comprises the broadcasting of standard frequencies and standard
time intervals from the Bureau's radio station WWV near Washington, D.C. The service
is continuous at all times day and night, from 10-kilowatt radio transmitters. The
services include: (1) standard radio frequencies, (2) standard time intervals accurately
synchronized with basic time signals, (3) standard audio frequencies, (4) standard
musical pitch, 440 cycles per second, corresponding to A above middle C.
Identification of atoms in ultra-microscopic particles of matter
no larger than 1/100,000 of an inch in diameter can be accomplished quickly and
accurately for the first time by a revolutionary new tool of science the electron
micro-analyzer developed experimentally by Dr. James Hillier of RCA Laboratories.
The new instrument, according to information released by RCA last month promises
to go far toward overcoming one of the great barriers to the accumulation of knowledge
about the infinitesimally small particles of matter of which all things are made.
Information vital to the solution of many practical problems in the physical, chemical,
and biological sciences can be obtained.
Close-up view of some of the controls on the board which calculates
Dr. James Hillier and Vladimir Zworykin study the action of the
new micro-analyzer. Latest addition to the increasing number of electronic aids
to chemistry, the instrument can identify particles of microscopic size.
"The vital question: 'Of what particular atoms, or chemical elements, are these
different particles of matter constructed?' can be answered by the electron micro-analyzer,"
Dr. Hillier explained. "For the first time, the scientist, using this new instrument,
will be able to determine the chemical constituents of a particle weighing only
10-15 or 1/1,000,000,000,000,000, grams. And, more important still, he
will be able to see the relationship of the particles to the rest of the specimen
In operation, the micro-analyzer uses an "electron needle" of extraordinarily
fine focus to knock other electrons loose from their parent atoms in the specimen,
measures the amount of energy lost by the incident electrons in the process, and
thereby reveals the specimen's chemical content.
"With the new instrument, the image of the specimen may be observed by means
of an electron microscope, which is incorporated as a part of the micro-analyzer,
and a selection made of the exact portion to be analyzed," Dr. Hillier said. "Then
by manipulation of a few controls, a photographic exposure is made of what we call
the 'electron velocity distribution.'
"This results in a series of small marks on the photographic plate, each one
of which indicates by its position the presence of a chemical element in the specimen.
Thus, with one exposure, information is obtained that would have required weeks
or months to obtain by present indirect methods, which too often result in failure."
In explaining how the instrument works, Dr. Hillier pointed out that in the table
of chemical elements each atom, or element, is differentiated from another by the
number of electrons surrounding the atom's nucleus. The electrons are arranged around
the nucleus in "shells," he added, and it is known how much energy, or voltage,
is required to knock holes in the shells of different atoms. "In the micro-analyzer,"
he continued, "the electrons of the 'needle' that strike the selected area of the
specimen are all moving with the same velocity, say 50,000 volts. After they have
passed through the specimen area, some of the electrons-the ones that struck atoms
traveling with less velocity, or energy.
"The next thing of importance in micro-analysis is the fact that the energy loss
suffered by the speeding electron is different for e a c h chemical element. What's
more, the differences are large enough to be easily distinguished by a method of
measuring electron velocities. If, for instance, one of the energy losses shown
is 298 volts, we know that a carbon atom has been struck; if it is 400 volts, the
element is identified as nitrogen, and so on."
Electron Microscopy has brought to light a virus-like organism
never before found in the human blood-stream, it was reported last month at the
first meeting of the Electron Microscopy Society of America.
Dr. Gregory Schwartzman, who made the discovery, reports that the virus belonged
to the group known as "pleuropneumonia-like
microorganisms." They have never been associated with any human disease, though
considered responsible for certain diseases of animals. They are then found in the
The discovery that these organisms which cause fatal diseases in animals are
also to be found in the human blood-stream has caused speculation as to whether
they may not play a part in the evolution of human diseases whose causes have until
now been a mystery.
Dr. Schwartzman also showed on the screen the first microphotographs ever made
of the virus which causes that type of meningitis known as "lymphatic choriomeningitis."
Other forms of meningitis are caused by bacteria.
Posted December 23, 2020