Robert B. Howell's investigative trip through Europe took place in fall of 1921. At this time the United States was seeing the beginnings of a broadcasting boom, mostly consisting of private stations sending out their programs for free to the general public. (The question of how all this would eventually be paid for was still largely unanswered.)

Meanwhile, the more cautious -- and largely government controlled -- European approach concentrated on revenue-producing subscription-based services, mostly directed toward businesses. And one city, Budapest, was generally unaffected by radio developments, as the Telefon Hirmondó celebrated its twenty-seventh birthday, still using telephone lines to distribute news and entertainment throughout the Hungarian capital. Meanwhile, Marconi was doing pioneering work with short waves, including experiments in range-finding, which would help lead to the development of radar.
 
The Book of Radio, Charles William Taussig, 1922.

Pages 288-308:

CHAPTER  XX

RADIO  IN  EUROPEAN  COUNTRIES
Postmaster General Hays sends Mr. R. B. Howell to Europe to investigate radio--Mr. Howell finds a telephone newspaper in Budapest that has been in operation since 1894--Broadcasting in England--Broadcasting in British East Africa--Radiophone on twenty-five meters--Short Wave Telegraphy and telephony--Marconi experiments with a one meter wave--Broadcasting from the German Government Station at Königswursterhausen, near Berlin--The Telefunken Radio Museum Receiving radio at the rate of 2,000 words per minute!--"Telefon Hirmondo" in Hungary--Listening to Wagner's "Walkyrie" on the "Telefon Hirmondo" as being produced at the Budapest Opera House--Very little being done in radio in Austria--Receiving time signals from Eiffel Tower in Paris on a six inch loop antenna--Vacuum tubes much cheaper in France--Radio on the Bourse in Amsterdam--Some interesting data on vacuum tubes abroad as compared to this country.
    After having discussed radio as practiced in the United States and the liberal manner in which the Government is developing the art for the use of the people, it is well to glance at Europe and see what is being done there. In most European countries the amateur and novice have few rights. Radio is looked upon to a considerable degree as a weapon of espionage, and therefore suspicious European countries take good care to control every phase of it.
    Postmaster General Hays, before his resignation, undertook to find out just what Europe was doing in radio and in broadcasting in particular. He therefore sent Mr. R. B. Howell abroad to make a report on what was happening over there.
    When the author explained to Postmaster General Work his intention of showing, by comparison, the liberality of the United States in the matter of radio, the Postmaster General was kind enough to let him have Mr. Howell's report, which heretofore had not been made public. Mr. Howell visited England, Germany, Hungary, Austria, France, and Holland where, through the courtesies extended to him as a representative of the United States government, he secured much interesting information.
    In most of the countries there are no amateurs, although considerable agitation in England and France may cause the restrictions against amateurs to be lessened. In Holland the government is more liberal toward the amateur.
    Mr. Howell found: That the "Telefon-Hirmondo"--a real telephone newspaper--was in operation in Budapest, as it has been constantly since its inception in 1894, and he was informed that three other European cities, following the example, had initiated similar enterprises.
    That broadcasting of news by radiophone had been recently initiated by the German Post Office Department from its Königswursterhausen Station, from which all portions of Germany were to be served, including the Lake Constance region, some 360 miles distant. That the Amsterdam Bourse had established a radiophone station in the Bourse building from which, since the 5th of January, 1921 (without any interruption what ever), Bourse quotations had been instantly supplied throughout Holland to some two hundred banks and brokerage houses. This is accomplished by stentor, stationed on the floor of the Bourse, repeating the quotations into a microphone connected with a radiophone apparatus in a room above.
    That American producers of radio apparatus are evidently abreast with European developments, and quite able to compete with foreign manufacturers. Especially are they far in advance in the matter of amateur apparatus.
    It was further found that in the opinion of the government officials and radio experts interviewed, there is no question as to the practicability of broadcasting with the radiophone; moreover, that it was their common belief that this service is one of the radiophone's great, if not its greatest, field of usefulness.
    England.--Through the courtesy of the American Embassy, Mr. Howell was introduced to Mr. F. J. Brown in charge of radio under the British Post Office Department, who placed him in contact with his technical force. About a year previously, the Marconi Company, under the auspices of the Department, experimented with the broadcasting of news from a station in the vicinity of London, a 12 kilowatt vacuum-tube sending set being utilized. Although the general results were satisfactory, except for the interference of shipping signals, nothing further has been done by the Post Office Department. However, a member of the technical force expressed the opinion that broadcasting by telephone would not be so generally useful in England as it might prove in the United States because Britishers have difficulty in understanding every other Britisher over a telephone, due to differences in pronunciation of the English language. He noted not a little irritation respecting the evident or assumed attempt of the private radio interests in England, France, Germany and the United States to control the radio patent situation and thus paralyze or bankrupt, independent manufacturers of radio apparatus, by litigation if necessary, where other means of eliminating competition failed. In closing the interview, Mr. Brown made a significant remark to the effect that, whereas others might control the patents, the government would still control the ether. Through Mr. Brown, Mr. Howell met Dr. Eccles, a consulting engineer of the Department. The Doctor expressed great interest in plans for broadcasting in the great American basin between the Allegheny and Rocky Mountains. He regarded this application of the radiophone as, perhaps, its chief field of usefulness. For covering, under all conditions, an area having a radius of 200 miles, he recommended the installation of a vacuum-tube sending set having an output of about 2˝ kilowatts.
    From other sources he learned that a project was on foot for the establishment of a radio telephone broadcasting station at Nairobe, British East Africa, where it is proposed to install a 10 kilowatt set, this energy being provided because of the absorptive power of the jungle regions. The enterprise is to be a semi-coöperative affair supported by English farmers and ranchmen of that region.
    In an interview with the Chief Engineer of the Marconi Company, Mr. Howell was assured that the Marconi Company would guarantee service under all conditions within a radius of 140 miles with a telephone sending set having a one-half kilowatt output equipped with an antenna supported by seventy-foot masts. The cost of such a set was quoted at about $4,000 including generator. The Marconi Company has recently been making some interesting experiments with the radio telephone between England and Holland, using a wave length of but 25 meters. The success achieved was attributed largely to the fact that the transmission was across the open sea. The Marconi Company and two other independent concerns with which he came in contact, supply amateur, vacuum-tube receiving sets, similar to those offered in the United States. The price quoted by one of the independent companies for a set with a detector and two steps of amplification, including tubes, accumulator and a B battery, was about $60. The tubes furnished with this apparatus were of French manufacture, extras being supplied at about $2 each.
    Radio with Wave Length under Fifteen Meters.--Experiments have been conducted in England for some time on the transmission of radio signals on very short waves. At a joint meeting of the American Institute of Electrical Engineers and the Institute of Radio Engineers, held in New York on June 20th, 1922, Senatore Guglielmo Marconi delivered an interesting paper, in which he dealt in some detail on the subject of short wave radio work.
    In 1895 and 1896, Marconi conducted experiments on short waves and obtained some promising results with waves not more than a few inches long. However, until comparatively recently, little has been done in short wave work.
    The study of short waves dates from the time of the discovery of electrical waves themselves, when Hertz conducted his original experiments. He used reflectors to prove the characteristics the waves and showed, among many other things, that the waves obeyed the ordinary optical laws of reflection.
    In 1896, when Marconi first went to England, he demonstrated to the late Sir William Preece, then Engineer-in-Chief of the British Post Office, the transmission and reception of intelligible signals over a distance of 1¾ miles, by means of short waves, using reflectors.
    As far back as 1899, in a paper read before the Institute of Electrical Engineers in London, Marconi showed that it was possible by means of short waves and reflectors, to project the rays in a beam in one direction only, instead of allowing them to spread all around, in such a way that they could not affect any receiver which happened to be out of the angle of propagation of the beam.
    After a lapse of many years, Marconi again took up the investigation of the subject of short wave radio in Italy, early in 1916, with the idea of using these short waves for certain war purposes. He was assisted by Mr. C. S. Franklin of the British Marconi Company, who has since followed up the subject with much thoroughness.
    Short wave radio makes very interesting experimenting, for at such low wave lengths as two or three meters, there is absolutely no interference from other radio stations, thus resembling the conditions in the early days of radio. Static is practically nonexistent. Strangely enough, there is some interference which is caused by the ignition apparatus of automobiles, motorcycles and motor boats. Such machines emit electrical waves from near zero to about forty meters in length.
    In his address before the Institute of Radio Engineers, Senatore Marconi referred to a conversation he had had with Dr. Alfred N. Goldsmith in reference to this interference. Dr. Goldsmith suggested that a receiving apparatus should be designed that could be tuned to the ignition on the motorcycles of policemen patrolling for speeding motorists. Dr. Goldsmith thought that such an arrangement might prove of interest to many habitual speeders, who frequently find themselves in trouble.
    In 1919, Mr. Franklin conducted experiments using a fifteen-meter wave length, generated by an electron tube. After many tests at lesser distances, a maximum of ninety-seven miles across land was spanned by radiophone. This was between London and Birmingham. Reflectors were used at both ends, and good, clear speech was exchanged at all times between the two places. Seven hundred watts power was used. About three hundred watts were actually radiated. The particular advantage of this type of short wave telephony was the excellence of the modulation and the fact that it was so directed that a station would have to be in an almost direct line with the transmitter, to pick up the signals.
    At the present time, by means of suitable electron tubes, it is practicable to produce waves from about twelve meters upwards, utilizing a power of several kilowatts. Probably the most practical use to which this short wave transmission has been put is for marine protection. Trials are being carried out under the supervision of Mr. Franklin with a revolving reflector erected at Inchkeith Island in the Firth of Forth, near Edinburgh. The transmitter and reflector revolving act as a kind of wireless lighthouse or beacon, and, by means of the revolving beam of electrical waves, it is possible for ships, when within a certain distance, to ascertain in foggy weather the bearing and position of the lighthouse.
    During the autumn of 1920, this experimental revolving reflector was erected and the first tests were carried out with the steamer Pharos. Using a four-meter wave length spark transmitter, a reflector and a single tube receiver, properly tuned on the ship, a working range of seven miles was obtained. The reflector was arranged so as to make a complete revolution every two minutes, and a distinctive signal was sent every half point of the compass. On the steamer it was ascertained that this enabled the bearing of the transmitter to be accurately determined within one-quarter point of the compass.
    By means of a clock-work arrangement, a distinctive letter is sent out every two points and short signs mark intermediate points and half points. This is done by having contact segments arranged on the base of the revolving reflector so that a definite signal is transmitted at every half or quarter point of the compass.
    One of the most interesting features of short-wave transmitting is that the strength of the signals is so regular at different points, that by means of a potentiometer, measuring the strength of the signals, a steamer can judge the distance it is from such a radio lighthouse by observing the strength of the signals. Of course, this latter characteristic of the short-wave transmitter will have to be carefully studied, so that standard apparatus can be produced for measuring distances.
    Not only can these short waves be directed, but they can be reflected and deflected by metallic objects miles away. It should, therefore, be possible to design apparatus by means of which a ship could radiate or project a divergent beam of these rays in any direction, which rays, if coming across a metallic object, such as another steamer or ship, would be reflected back to a receiver screened from the local transmitter on the sending ship, and thereby immediately reveal the presence and bearing of the other ship in foggy or thick weather.
    Just prior to the conclusion of Senatore Marconi's address, he demonstrated the working of a roughly constructed, one-meter, wave transmitter and reflector. The demonstration showed, conclusively, that the waves are directed very much in the same manner as a searchlight directs a beam of light. Unless the reflector was pointed toward the receiver, no signals were heard in the receiver.
    In order to secure a reflector or antenna sufficiently large for use with higher power, and yet transmit on these exceptionally low wave lengths, it is necessary to make the reflector or antenna with many small metallic strips, which are each tuned to the transmitting wave length and are inductively coupled to one another and to the transmitter.
    The reflector with which Senatore Marconi demonstrated, consisted of many of these small strips. The complete reflector was a concave form, about six feet in diameter, and two and a half feet high.
    At this writing, experiments are still being conducted on short-wave transmission and reception, in England.
    Germany.--Upon arriving in Berlin, Mr. Howell was placed in contact, through the courtesy of the American Consulate, with Herr Lindow, head of the telegraph and telephone bureau of the German Post Office Department, from whom and his assistant, Dr. Arendt, he learned that the broadcasting of news has been recently initiated at the government's Königswursterhausen station some thirty miles distant from Berlin. Bulletins supplied by a news agency were being radiophoned in accord with a fixed daily program of some fifty-one receiving stations located throughout Germany, and it was expected that this number would be increased to about 1,000 stations by the first of the year. Subsequently, when at the Telefunken Office he was afforded the opportunity of listening in, broadcasting then being in progress, and heard distinctly the details of a recent murder. Under German regulations, no one is allowed to operate a sending station or install a receiving set without a license from the government, and this license is only granted for receiving stations to those who pay for the service afforded. It is proposed to radiate different classes of news with different wave lengths respectively, each receiving set being permanently adjusted to receive the particular kind of news desired, thus enabling the government to charge subscribers, desiring more than one class of news, in accord with the service rendered. Of course, this means a self-supporting broadcasting service, a development possible where the government absolutely controls the installation and use of receiving apparatus. The German Post Office Department considers broadcasting as one of the most promising developments in connection with the radio telephone, and believes that through the control of receiving stations the greatest possible results will be assured. As may be assumed, there has been little or no development of amateur wireless in Germany, the manufacture of receiving sets being largely confined to the so-called commercial types. A series of experiments were conducted by the Department with a 10-kilowatt set, prior to the initiation of regular telephone broadcasting from which were adduced the following facts:
  1. That the efficiency of service depends much upon the stentor's quality of voice, enunciation and training.
  2. That men and women are about equally effective as stentors.
  3. That 100% results were obtained at the farthest limits of Germany, while stations nearer dropped below par, due probably to the personal equation at the receiving station, atmospheric conditions or both.
  4. That receiving sets equipped with detectors alone were not satisfactory beyond 150 miles.
  5. That a vessel on its way to South America heard this station until more than 2,100 miles distant.

    Experiments at the Nauen Station, using a high-frequency alternator and 130 kilowatts in the antenna, demonstrated that speech and music could be rendered clearly audible throughout Europe from Madrid to Bucharest without the use of amplifiers.
    Through the courtesy of Dr. Arendt, Mr. Howell was shown through the radio museum of the Telefunken, the chief radio concern of Germany, and there saw the latest model of a receiving set that is to be installed by the Post Office Department. It consists of an upright panel, rising above a small desk, to which is attached the apparatus, which, after being so tuned as to leave but one adjustment for the operator, is locked and the key retained by an inspector. At the top of the panel is an additional apparatus controlling a relay bell which can be rung from the sending station by a series of dots and dashes, thus rendering it possible to announce extra news, or news afforded at times other than as provided in the regular program. The price of this receiving apparatus is about $350. The Telefunken also offered a one-kilowatt telephone sending set including one rectifying tube, two transmitting tubes of 500 watts each, with motor-generator and switchboard, for $6,125.
    While visiting the laboratory of Dr. Erick F. Ruth, he learned for the first time that the Amsterdam Bourse in Holland was broadcasting Bourse news. This laboratory offered their type 13 CLT sending station, for both telephone and telegraph, one-kilowatt output, wave lengths from 500 to 1,000 meters, guaranteed range over 200 miles, for $6,500. This apparatus was complete including a receiving set and spare parts. A similar apparatus having a 250 watt output, wave lengths 375 to 600 meters, was $2,250. The price of a three-tube receiving set claimed to be fool proof, designed for wave lengths from 375 to 2,000 meters, without batteries, was quoted at about $60, but they would not sell this apparatus until after consultation with New York. At this laboratory, Mr. Howell also witnessed the operation of a recently perfected electro-static apparatus for receiving and recording telegraph messages sent either by wire or wireless, that would register telegraph code letters on a tape at a rate as high as 2,000 per minute. Subsequently, in Vienna, he was told by a radio engineer that he considered this apparatus the most striking development presented at the recent Jena Conference of Germanic physicists. The apparatus was not regularly on the market, but the price therefor, when offered, will be about $800.
    Hungary.--With the exception of government telegraph installations, there was no radio development evident in Budapest. Mr. Howell did find, however, the Budapest Telephone newspaper, known as the Telefon Hirmondo, to be still flourishing after some twenty-seven years of "publication."
    This enterprise consists of forty-two wire-telephone party lines, among which are distributed some 6,000 subscribers who, though unable to call central, can all be talked to at one and the same time by a man in the central office, called a stentor. News, instruction, and entertainment is afforded by this "newspaper" in accord with a regular daily program. The service begins at nine in the morning and continues until ten o'clock at night. Besides, short or continued stories are read to subscribers each afternoon, supplemented on several days of the week, by story telling for children. Likewise, lectures and speeches may be heard by those who prefer to stay at home. During the war, an hour of instruction in the French language was afforded each afternoon, but recently English has supplanted French in the Hirmondo's curriculum, and the course is immensely popular. Under the Empire, the Royal Band gave afternoon concerts and the music was transmitted to the Hirmondo's subscribers through microphones stationed at the band stand, but as there is no longer such an imperial organization to discourse, this service has been necessarily terminated. However, opera is afforded each evening to every home served by this enterprise. Mr. Howell was in the offices of the Hirmondo at five o'clock in the afternoon, or about an hour before opera begins in that city, and heard the stentor reading into the microphone the personnel of the artists on the program that evening. Later, upon the invitation of the manager, he went to his home where they listened to Wagner's "Walkyrie" communicated from microphones located in and about the stage of the Budapest Opera House. He found listening to opera under such conditions highly pleasing, as a human touch was communicated, such as is not possible with a phonograph, in fact, one could shut one's eyes and almost imagine the stage in front. Plans were on foot for the radio reception of opera from Berlin and to transfer the same directly to the Hirmondo's wires. The cost of this service prior to the war was sixty-one cents per month, each subscriber having two receivers; however, more receivers could be had at a slightly increased cost. Because of the depreciation of Hungarian currency, at a rate more rapid than the Hirmondo has been able to increase its charges, the cost per month is now only about four cents. The Manager stated that there is a great demand for extensions of the Hirmondo's lines, but unfortunately capital is not available for the purpose. It was also stated that similar enterprises have been initiated in Lyons, France; Milan and Rome, Italy. However, such developments in these cities are in their infancy.
    On inquiry in regard to using the system for advertising purposes, it was stated that this had been attempted but that subscribers resented what they deemed an interference with the service and, as a consequence, the idea has all but been abandoned. Advertisers, however, are quite willing to use the service in a measure. In fact, the opera house authorities and various Gypsy bands look upon the advertising opportunity offered by the Hirmondo as of so much value that they grant the privilege of placing microphones for the transmission of their music and entertainment, practically without charge.
    Austria.--That Austrian government officials in charge of telegraphs and telephones had given little attention to the use of the radiophone, was evidenced by the interview afforded through the courtesy of the American Embassy in Vienna. The difficulties of the Department, due to a large deficit and a further depreciation of the currency, seemed to have rendered even the thought of new developments out of the question. It was stated that Berlin opera had been received at the government telegraph stations within the city with highly satisfactory results but further than this nothing of value was elicited.
    Mr. Howell found but one manufactory of radio apparatus in Vienna and that was rather a laboratory than a manufacturing plant and produced tubes and receiving sets only. These sets were elaborate and designed to utilize a loop rather than an antenna, with which it was claimed that all of the large radio telegraph stations in Europe could be heard. One receiving set offered consisted of a panel, pyramidal in form, surmounted by a revolving loop five feet square and equipped with two detector tubes, a five step high frequency and a three step low frequency amplifier. The price of this apparatus complete, including tubes, accumulators and B battery, was $391. Additional tubes would be supplied at $1.60 each.
    France.--The Naval Attache's office in connection with the American Embassy in Paris gave every possible facility at its command, for investigations in Paris, affording a personal introduction to M. Laffont, Under-Secretary of State for the French Post Office Department, and M. Brouin, director of telegraph exploitation for that Department. From these gentlemen, it was learned that there had been no development of broadcasting in France by the radio telephone though the radio telegraph was being used therefor to a limited extent, principally in connection with weather reports. General Ferrie, Chief of Radio for the French Army, who was subsequently interviewed, expressed his approval of the idea of broadcasting news by radio telephone, and pronounced it wholly feasible. He stated that in France there were three systems of wiring utilized for receiving sets--the Marec, the de Bellescise and the Levy. He expressed no preference for any one of these systems, adding that all were good, each having special advantages and disadvantages. As to receiving tubes, he stated that the French government paid therefor twelve francs each, or about ninety cents. In his office, there was a very small and compact receiving set, consisting of a crystal detector with two amplifying tubes, equipped with a loop about six inches square, dry batteries being used for both filaments and plates. This set rendered signals from the Eiffel Tower clearly audible throughout the room.
    Through the courtesy of Commandant Brenot, Chief Engineer of the Compagnie Générale de Télégraphie a visit was afforded to the company's plant in the outskirts of Paris, where Mr. Howell inspected a number of sending and receiving sets and heard the reproduction of a song by Melba that had been transmitted by radio from London a year previously and impressed upon a phonographic disk. Commandant Brenot also expressed his unqualified belief in the feasibility of broadcasting by the radio telephone and suggested that the receiving problem might be simplified by installing powerful sending stations and utilizing crystal detectors for receiving, with tube amplification where necessary. He stated there was no doubt that a 2½ kilowatt sending set would suffice under all conditions for 200 miles, and cited some of the company's recent experiments over water with but 35 watts in the antenna. Crystal detectors, without amplification, rendered verbal messages clearly audible at a distance of 150 miles which can be considered excellent work.
    The Société Indépendante de Télégraphie afforded quotations for apparatus as follows:
    A one-kilowatt tube station, with cabinet including sending and receiving apparatus, complete, except accumulators and antenna, about $4,500.
    The quotations for vacuum tubes were: 250 watt oscillators about $21 each; tubes for detection and amplification about $1.75 each. This was the only concern from which quotations could be secured, others referring to their American representatives.
    Holland.--Though Mr. Howell had passed through Holland on his way to Germany, it was determined to return and visit Amsterdam for the investigation of rumors that had subsequently reached him, of broadcasting from that city. Due to the courtesy of the American Consul at that point, he was promptly put in touch with the officials of the Amsterdam Bourse and found that the broadcasting of Bourse news had been carried on without interference for the previous ten months, thus serving some 200 banks and brokerage establishments throughout Holland. The sending equipment of this station is located in a small room on the floor above the Bourse, and consists of a motor-generator affording a current of 400 volts, which is stepped up to 4,000 volts for the plates. The panel is equipped with two rectifying tubes, three one-kilowatt oscillators, a one-kilowatt modulator and two one-kilowatt amplifiers, affording an output of about 1½ kilowatts in the antenna. The operating force consists of an electrician at the apparatus and a stentor on the floor of the Bourse. Within a radius of twelve miles, Galena crystal detectors are used, from twelve to thirty miles, tube detectors, and beyond thirty miles, tube detectors with one or more amplifiers, as may be necessary. The sending apparatus was installed by the Holland branch of the Marconi Company which receives a rental therefor of about $1,700 a year. The receiving sets are also supplied, installed and maintained by the company at an annual charge of about $66 per station. The Bourse charges for its service about $34 per annum, making the total charge to each subscriber $100 per annum. After paying the rental for sending apparatus to the Marconi Company, there remains for the Bourse about $5,000 per year to pay salaries of technician, stentor, for replacement of tubes, and for energy. The service afforded has been highly satisfactory, it having been continuous during the sessions of the Bourse without exception, since the 5th day of January, 1921.
    Vacuum Tubes.--The vacuum tube, or so-called radio valve, which is largely responsible for the present-day, practical development of wireless telephony, is still covered by patents in the United States, but it may be manufactured freely in nearly all other countries of the world. The result is that a 500 watt oscillator, selling in this country for $175, can be purchased in England for about $36. Likewise receiving tubes are quoted here at from $6 to $7.50, while the French government buys detectors and amplifiers at $.90 each. And the irony of the situation is that, so far as the general public is concerned, excluding shipping, there are probably more tubes purchased by this class of users in the United States, than in all of the rest of the world combined.
    No foundation could be discovered for the rumor that tubes with metal instead of glass envelopes were in course of development. However, it was found that the Mullard Radio Valve Company of London, an independent concern, was producing fused quartz oscillators of about one-half the size of ordinary glass tubes of the same power. The life of the filaments of the tubes, offered by this concern, was about eight hundred hours; however, the filaments could be renewed, the expense of such renewals being about 25 per cent of the tubes' first cost. Mr. Howell learned that the Marconi-Osram Valve Company had made oscillators up to 10 kilowatts in size, and expected to produce them as large as 16 kilowatts. He did not learn anything regarding so-called "Cold Electrode" tubes. However, the two companies above referred to are producing low temperature filament tubes, the characteristics of three types of which are as follows:

MARCONI-OSRAM  COMPANY
TypeAmperesVoltsLifePrice
A. R. Tube . .
I. A. Tube . . .		.4  
.12		1.7
1.7		1,000 hours
1,000 hours		---
---


MULLARD  COMPANY
TypeAmperesVoltsLifePrice
L. F.  . . . . ..4 1.52,000 hours$5.75