Rainey, Challenor W.

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 The Knowledge Bank at The Ohio State University Ohio State Engineer   Title:  Thomas Alva Edison Creators:  Rainey, Challenor W. Issue Date:  Nov-1929 Publisher:  Ohio State University, College of Engineering Citation:  Ohio State Engineer, vol. 13, no. 2 (November, 1929), 6-7. URI:  http://hdl.handle.net/1811/34615  Appears in Collections: Ohio State Engineer: Volume 13, no. 2 (November, 1929)     T H E O H I O S T A T E E N G I N E E RTHOMAS ALVA EDISONBy CHALLENOR W. RAINEY, E.E. 2It would be hard indeed to compute the worthof Thomas Edison's gifts to the world. We hearthis great name again and again without realiz-ing just how much it affects us. The work of thismarvelous practical inventor has helped, indirect-ly though it may be, to hasten our modern indus-try and comforts more than the average personrealizes. The reason Edison's inventions were sosuccessful may be summed up in his own words,"I have made it a practice never to work on anyline not purely practical and useful."Of Edison's early life little need be said. How-ever, it should be noted how active were his youth-ful days. First, a newsboy, journalist, and editor;then, a chemical and physical experimentor; andnext, an expert telegrapher, we have his earlypreparation for the life which was to follow. Wefirst hear of him in his new life when on Octo-ber 13, 1868, he was granted his first patent (anelectro-graphic vote recorder).His first important accomplishments were intelegraphy. In this line he invented a districtand chemical telegraph, a stock printer, the du-plex system, and the marvelous quadruplex trans-mitter system which allows four messages to besent over the same wire at the same time. Thequadruplex gave rise to an invention whichstartled the world—the phonograph. While lis-tening to the audible sounds of a quadruplex ma-chine and noting the musical sounds which camefrom its revolving disc, he got one of his greatideas, that of reproducing sound. Hurriedly hedrew up the plans for an experiment and gavethem to a co-worker who made the apparatus.This consisted of a wax cylinder, grooved and cov-ered with tinfoil, fixed on a threaded shaft so thatit could have a rotary as well as a horizontalmotion. When the apparatus was completed Edi-son shouted into the diaphragm the memorablewords, "Mary had a little lamb." Th,e reproduc-tion of this was so clear that witnesses of thisexperiment were amazed. The development ofthis device has brought pleasure and profit to un-told millions.Late in 1877 Edison improved Alexander Gra-ham Bell's telephone by using a carbon buttontransmitter. This instrument, which greatly im-proved telephone conversation, is still in use today.On October 15, 1878, Edison made his first plungeinto the field of electric lighting when he inventeda thermostatic regulator designed to keep the cur-rent to a safe value in the platinum-iridium lamp.When Edison seriously considered electric il-lumination, there was, already, a practical gassystem in use in the cities where industry de-manded it. It is small wonder, then, that only afew men were working on the problem of an elec-tric lamp.Edison saw the limitations of the arc lamp andwas fired by the idea of producing an incandes-cent lamp. He made a complete analysis of theproblem and commenced to develop it. Edisondescribed this occasion as follows:"We soon saw that the subdivision (of electricEdison's First Successful Incandescent Lamp.light) never could be accomplished unless eachlight was independent of the others. Now it wasplain enough they would not burn in series.Hence they must burn in multiple arc. It waswith this conviction that I started. I was firedwith the idea of the incandescent lamp as opposedto the arc lamp, so I went to work and got somevery fine platinum wire drawn. Experiment withthis, however, resulted in failure, and then wetried mixing in with the platinum about 10 percent of iridium, but we could not force that highenough without melting it. After that came a lotof experimenting—covering the wire with theoxide of cerium and a number of other things."I then took a cylinder of zirconia and woundabout a hundred feet of the fine platium wire,coated with magnesia, on it. What I was afterwas getting a high resistance lamp, and I madeone that worked way up to 40 ohms. But theoxide developed the phenomena now familiar toelectricians, and the lamp short-circuited itself.After that we went fishing around and trying allsorts of shapes and things to make a filament thatwould stand. We tried silicon and boron, and alot of things that I have forgotten now. I neverthought in those days that a carbon filament wouldanswer, because a fine hair of carbon was so sensi-tive to oxidation. Finally, I thought I would tryit because we had got a very high vacuum."We sent out and bought some cotton thread,carbonized it a,nd made the first filament. Wehad already managed to get a pretty high vacuumNOVEMBER, 1929T H E O H I O S T A T E E N G I N E E Rand so we thought the filament would not oxidize.We built the lamp and turned on the current. Itglowed, and in the first few breathless minuteswe measured its resistance quickly and found itwas 275 ohms—all we wanted. Then we sat downand looked at that lamp. We wanted to see howlong it would burn. The problem was solved—ifthe filament would last. The day was—let mesee—October 21, 1879. We sat and. looked, andthe lamp continued to burn, and the longer itburned the more fascinated we were. None of uscould go to bed, and there was no sleep for anyof us for forty hours. We just sat and watched itwith anxiety growing into elation. It lasted 45hours, and then I said, 'If it will burn 45 hoursnow, I know I can make it burn a hundred.' Wesaw that carbon was what we wanted. I then be-gan to try various things, and finally I carbonizeda strip of bamboo from a Japanese fan, and sawthat I was on the right track."Now came the great task of putting the lampon the market. The gas lighting industry hadgained a strong foothold and was affording il-lumination at reasonable rates. In order to com-pete with gas lighting, Edison had to perfect asystem that would give better service. Edisonsaid of his problem:"A complete system of distribution for elec-tricity had to be evolved, and as I had to competewith the ga§ system this had to be commerciallyefficient and economical. A commercially soundnetwork of distribution had to permit being placedbelow or above ground and had to be accessibleat all points and be capable of being tapped any-where."I had to devise a system of metering electricityin the same way as gas was metered, so that Icould measure the amount of electricity used byeach customer. These meters had to be accurateso that we could charge correctly for the currentused, and also they had to be cheap to make andeasy to read and keep in working order."Means and ways had also to be devised formaintaining an even voltage everywhere on thesystem. The lamps nearest the dynamo had toreceive the same current as the lamps fartheraway. The burning out or breaking of lampsmust not affect those remaining in the circuit,and means had to be provided to prevent violentfluctuations of current."One of the largest problems of all was that Ihad to build dynamos more efficient and largerthan any then made. Many electrical people statedthat the internal resistance of the armature shouldbe equal to the external resistance; but I madeup my mind that I wanted to sell all the electricityI made and not waste half in the machine, so Imade by internal resistance small and got out 90per cent of salable energy."Over and above all these things, many otherdevices had to be invented and perfected. Devicesto prevent excessive currents, proper switchinggear, lamp holders, chandeliers, and all mannerof details that were necessary to make a completesystem of electric lighting that could compete,successfully, with the gas system. Such was thework to be done in the early part of 1878. Thetask was enormous, but we put our shoulders tothe wheel, and in a year and a half we had a sys-tem of electric lighting that was a success."Such was the thoroughness with which EdisonNOVEMBER, 1929Interior of Pearl Street Station, Edison Electric Illuminating Company,New York, 1882, showing six generators, total capacity 750 h. p.attacked this gigantic problem. Here we haveone element of his greatness: that of complete-ness.From the very beginning Edison proceeded un-hampered by the influence of other men's work.The Pearl Street Station, the first electric sta-tion built by Edison, was the forerunner of thegreat network of electric power station whichnow cover the world. When it first went intooperation. 400 lamps were lit, but the systemcould supply 85 buildings containing a total of2300 lamps.Since the successful production and demonstra-tion of the electric lamp Edison has continouslybeen engaged in many types of experiments.AUTHOR'S NOTE.—The author acknowledges indebtedness to the Na-tional Lamp Works of The General Electric Company for the illustra-tions and some of the material. He also acknowledges his indebtednessfor some of the material to his father, L. T. Rainey, who worked withMr. Edison during 1884-5, and who is now general manager of theCincinnati office of the General Electric Co.

Thomas Alva Edison

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Thomas Alva Edison

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