Discussion of "A History of Some Foundations of Modern Radio-Electronics Technology" Page 1256

that the “blue haze” was due to gas and sought better evacuation. The best of the tubes de Forest had left with Western were repeatedly pushed to the highest plate voltages they would stand to clean up the gas in them. Other tubes were obtained from the manufacturer, McCandless; the electrical characteristics were measured; and by the end of the year Arnold and his assistants had a fair mastery of the newcomer. There was ordered from Germany the latest type of vacuum pump (Gaede, molecular); and upon its arrival in April, 1913, Arnold started making his own tubes of high vacuum and greatly improved design.

Thus, the Western Electric Company engineers were already familiar with the audion when in January, 1913 Lowenstein’s “black box” was opened to them. They had expected to find something new, and were disappointed when there appeared only “the ordinary audion” as they reported. The negative grid was noted and Colpitts in his report mentioned that the question of its potential was to be studied and the company should be free to employ any polarization. This point must have seemed minor to his boss Jewett, for he lost sight of it. An examination of the patent papers submitted by Hammond revealed that the three claims stood rejected by the Patent Examiner on two de Forest patents. The work of the Austro-German von Lieben group was then coming to attention, on which the Lowenstein claims were soon to be rejected by the Patent Office. Altogether, the American Telephone and Telegraph Company’s patent attorney Lockwood reported, “I do not see that the Lowenstein people really have anything to sell,” and since they were unable to demonstrate to the contrary, the case was dropped. But Lowenstein’s patent attorney, M. C. Massie, was persistent and resourceful. A few years later he managed to get allowed claims on the negative grid. Imagine the surprise of the telephone patent people when the patent was issued in 1917 with claims that read on the grid polarization that the engineers had found to be necessary and that was then in use! So, the patent was bought, quietly, for the very considerable sum of $150,000. Massie told the writer afterward that the company originally could have had the patent for $20,000 and he had finally boosted the price to $200,000, to come down to the amount agreed upon!

Thereby hangs a supplementary tale too good not to note. The writer had known Lowenstein as a fellow IREer; had been at the American Telephone and Telegraph Company’s headquarters on radio matters during all this time, and had been aware of company contacts with Fritz, but without knowing the subject matter. Imagine then, his surprise upon meeting Lowenstein one lunch time in 1918 in the German restaurant beneath the Woolworth Building, and being shown a check to Fritz’s order from the American Telephone and Telegraph Company for the $150,000! To the question of what was it all about, he cheerfully explained, and then observed in his quizzical way, “And to think, for just a little dry battery!” The appropriate rejoinder would have been, “But in the right place!” Fritz was so pleased with his accomplishment that he carried the exhibit, a photostat, around with him to show his friends, as an Indian would a scalp! Had the writer not known Fritz personally he would have been unaware of the telephone company’s payment, for so unheralded had it been at headquarters! Incidentally, Fritz’s insertion of the audion amplifier in the receiving branch of his office telephone in 1911 constituted the first application of that revolutionary device to the Bell System, sub rosa as it was!

The von Lieben Group

Candor requires that we recall at this point something of another group of inventors whose work with the cathode-ray tube was contemporary with that in the U. S. and had been directed from the beginning at the problem of the telephone repeater. The Austrian Robert von Lieben patented in Germany in 1906¹⁹ a telephone repeater comprising a thermionic three-element beam-deflection tube intended to be of high vacuum. It was scientifically sound but not successful. The inventor, with two associates, Reisz and Strauss, fell back upon the gaseous, ionic, type of thermionic tube beginning about 1909. In 1910 several forms were patented in Germany.²⁰ One of these used an intervening grid for control and was applied for in the U. S. on January 30, 1911, and issued September 17, 1912, No. 1,038,901. It was this patent as well as earlier de Forest audion patents, that was cited against Lowenstein. Thereby he was prevented from covering the audion as an amplifier broadly, his invention reducing to the negative grid feature.

While it seems clear that Lowenstein started on his amplifier quest from de Forest’s audion in 1909–1910, his more successful renewed pursuit of it in 1911 may well have been stimulated by some knowledge of the von Lieben work having seeped across the Atlantic. He is known to have followed the German-language literature, and Hammond’s visit to Germany in the summer of 1911 had made Hammond “quite familiar with the art in Europe” as he wrote Thompson. Since Lowenstein did not get the blocking condenser out of the grid circuit until late in 1911 (by which time the von Lieben group already were in the U. S. Patent Office), he cannot be credited with having been the first to have arrived at the grid thermionic amplifier even in the U. S. But he was the first with the type of device that was to win out. The initial promise of the von Lieben mercury-vapor ionic grid tube proved to be chimerical, for the device was erratic and noisy and did not lead to the final answer, the high-vacuum tube. Fortunately for de Forest and Lowenstein, the audion did! Actually, Lowenstein and Hammond, by coming into the picture when they did, alerting de Forest, and leading on to the two large electrical companies, performed a major service.

High-Vacuum Tube

Singularly enough, as the paper indicates, both of these big companies, the American Telephone and Telegraph Company (and its associates of the Bell system), and the General Electric Company, learned of the audion about the same time, late October and early November, 1912. Each went immediately about the improvement of the mysterious little tube, unknown to the other. Although up to that point the mode of operation had been a mystery, and the tube was flimsy, erratic (hardly any two were quite alike), and unable to carry a material load, within a year or so each company had mastered the device and was producing a tube characterized by regularity and reproducibility, whereby it became the revolutionary electronic tool it did. The contribution of these companies was, then, a major one. It followed from the application of the scientific knowledge of the time to the temperamental little tube, first in diagnosing its troubles, and then in applying the remedies: high vacuum and higher voltage, better filament emission and longer life, and circuits properly designed to go with it. No wonder these two great companies locked horns over the great high-vacuum improvement when the General Electric Company sought and obtained a patent on it on behalf of Langmuir. Arnold more modestly had regarded his high-vacuum tube as an application of scientific knowledge rather than invention. The contest continued many years, with the Supreme Court finally sustaining Arnold’s view. He was given credit for having anticipated Langmuir in November, 1912, and de Forest was recognized to have gone part way toward the high-vacuum tube even earlier without knowing the physics of it. The Langmuir patent was invalidated on the basis that, “. . . the relationship of the degree of vacuum within the tube, to ionization, and hence to the stability and effectiveness of the discharge passing from cathode to anode, was known to the art when Langmuir began his experiments.” The reference cited is a paper by Lilienfeld.²¹ It is pointed to as having “. . . made a complete and explicit disclosure of the essentials . . . .” The decision went on to recognize that, “Lilienfeld also deduced from meter readings and stated the 3/2 power relation of current to voltage, as Langmuir later stated it in his patent. From this the conclusion is inescapable that Lilienfeld knew and stated, in terms which could be understood by those skilled in the art, that in a high vacuum the current produced is under control, stable, and reproducible; and, as he employed high voltages, that higher power levels of the discharge may be obtained . . . .”²²

To return more directly to the Hammond-Purington paper: it must have been early November, 1912, rather than “in late Oc-

¹⁹ German Patent No. 179,807; patented March 4, 1906; issued November 19, 1906.
²⁰ German Patent No. 236,716; patented September 4, 1910; issued July 11, 1911. Corresponding U. S. Patent No. 1,059,763; applied for January 30, 1911; issued April 22, 1913.
German Patent No. 249,142; patented December 20, 1910; issued July 12, 1912. Corresponding U. S. Patent No. 1,038,901; applied for January 30, 1911; issued September 17, 1912.
²¹ J. E. Lilienfeld, “The conduction of electricity in extreme vacuum,” Ann. Phys., vol. 32, no. 9, pp. 673–738; 1910.
²² (664) de Forest Radio Co., Petitioner, vs General Electric Co. (283 U. S. 664–686). Published in Book 75, “Cases Argued and Decided in the Supreme Court of the United States, October Term, 1930,” The Lawyers Cooperative Publishing Co., Rochester, N. Y., vol. 131, pp. 1339–1349.
Also reported by W. R. Ballard, “The high vacuum tube comes before the Supreme Court,” Bell. Labs. Record, vol. 9, pp. 513–516; July, 1931.