[D8955ABX], Letter from Edwin M Fox to Thomas Alva Edison, May 24th, 1889


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[D8955ABX], Letter from Edwin M Fox to Thomas Alva Edison, May 24th, 1889

Editor's Notes

[Ans May 28/89] Dear Mr. Edison: A long while ago I became impressed with the belief that the phonograph could be run by a spring and I made numerous experiments In that direction with my Tainter machine. The results, while not altogether satisfactory demonstrated the correctness of my theory but at that time I was not so much interested financially in the matter as I am at present, so I proceeded slowly. On receiving my Edison machine, from the Metropolitan Co, a few weeks ago, I continued my experiments and the result is that I have now running in my office your machine propelled with sping power. It runs beautifully. My attachment consists of a pwerful spring coiled in the usual way inside a drum, which on uncoiling revolves a shaft which is geared to the main screw shaft of the phonograph. The motor part of the machine is of course removed. For a governor I use a tiny fan on a worm revolving at a very high rate of speed by means of clock gear engaged by a gear on the shaft rotated by the spring. A little movable arm is pivoted near this fan which when pressed engages the fan and stops the machine. The spring is wound by pulling a lever four inches long a few times. On the spring being wound up the phonograph revolves at 40 revolutions per minute with perfect evenness and continues running for six minutes unless sooner stopped by pressing the little arm above mentioned. There is apparently no diminution of speed as the spring uncoils. It stops short when run down. It is obvious that if I use a larger and more powerful spring that I can get a longer action. I have seen the leading spring men in New York in the course of my experiements and they tell me that they can furnish with me springs that they gurantee will run over thirty minutes and do my work but for all practical purposes six minutes is long enough for it is no trouble to the user to pull the little handle and thus wind it up again. The weight of my entire appartus is less than seven pounds and presents a neat appearance when coupled up with the phonograph. The drum and lever handle are only to be seen, at the left of the phonograph frame which latter is elevated a few inches on the table to permit the governor and its gearing to go undeneath thus being out of sight. The starting and stopping are simplicity itself. The start, the user of the phonograph m erely pulls the drum arm towards him a few times, releases the governor stop and the cylinder will revolve at the speed above mentioned for six minutes. To stop he merely depresses the little arm that engages the fan. The phonograph proper remains exactly as before. The only difference is that the motor and battery are removed. There is no noise in the working of the gear. The machinists who have been doing the work for me say that my attachment can be manufactured in quantity and connected with the phonogrph for less than seven dollars each. The one I have now running is the last of nearly a dozen that I have had constructed but found faculty in one respect or another. You will notice that I run at 40 revolutions per minute. I have run at all speeds from a snails pace to over 125 per minute but I find excellent results at forty although, as you know speed is only a matter of gearing. I apparently have a surplus of power even at high speed. The effect of slow running you will appreciate is very important for a cylinder such as you use can be made at the speed I am now running, to carry several times as many words as it now holds at the speed of over 100. In other words you can make your cylinder only two or three inches in length and thus do away with the objectionable feature of bulk in mailing. I have made application for letters patent for my spring attachment and I believe that I will obtain strong claim on the same. It is my wish to turn it over to you on terms that are fair and right for that is all I want and I am satisfied from my knowledge of your honorable character that everything will be satisfactery. You will recognize that its application to the phonograph is a death blow to the graphophone for with the perfect reproduction accomplished by your machine, working with a spring that a child can handle, no person would think of using a graphphone. Immediately upon receipt of a telegram from you I will bring it to your laboratory so that you can examine it at your leisure. Sincerely Yours Edwin M Fox





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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
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