The Petit - Prescott Patent of 1904.
In early January 1901, the United States Patent Office was sent an application by one Ademor Napoleon Petit. It was for something that was both novel at the time, yet to us, prosaic in the extreme. Quite simply, Petit wanted to patent the double-sided gramophone record. This is not a serious analysis of the matter; I am not qualified to make one. It is merely a layman’s summary of the improvements Petit claimed for his invention.
It was not simply like attempting to patent the idea of writing on both sides of a sheet of paper. Such a patent application would never have been allowed, one assumes. No; Petit thought that pressing a record with a groove on one side, and not on the other, was simply a bad idea. The two sides of the disc underwent different degrees of deformation during pressing. On the recorded side, the spreading of the hot plastic material would be impeded by the ridges on the stamper, while on the smooth side there would be no such effect. Therefore the two sides of the disc had different in mechanical properties; and above all, the side bearing the groove would be imperfectly pressed because of the asymmetrical movement and distortion of the material as it spread during pressing.
By having a double-sided record, Petit claimed, both the sides would be pressed better: “My invention”, Petit said, “comprehends using two opposing matrices between which the mass of plastic material is compressed under heavy pressure, thereby to produce a double-record-faced disk. The sound record at either face is of such a disk is superior in quality and perfection to that of the single record of a single-record-faced disc made as heretofore, because the presence of the opposing matrices with their roughened or relief surfaces resists radial flow or spread of material at both faces of the disk, thus not only reducing the flow, but insuring uniformity at both faces of the disk of whatever flow there may be.”
Petit also points out that not only are both sides better pressed, they are also more similar in sound – ‘phonetically uniform’ as he puts it. He certainly has a point there: if you played a two-part work on single-sided discs in 1901 (assuming any had appeared that early), the ‘pair’ on which you spent your hard-earned cash might well have been pressed weeks or even months apart, and on quite different grades of material.
Petit goes on to claim that the double-sided disc also has a lower surface noise than a single-sided one, in that more ‘work’ has been done on the material, and that is therefore smoother: “The material is… thinnest at that part of the disc in which the record groove or grooves are formed, the under surface of the disc being indented opposite the record-groove on the upper surface. This greater density means that the molecules have been forced closer together. This reduces the scraping or hissing sound which usually accompanies sound reproduction in a talking machine. This scraping or hissing or series of sounds like small explosions are produced by the stylus jumping across the minute spaces between the molecules. The noise is therefore reduced when the molecules are arranged more closely together.”
He also points out that “two records may be impressed at the same cost for material and labor as heretofore required for one”, which I suppose was the real core of the patent; but is put, modestly, far down the list. Petit is now a cascade of creativity in full spate; he suggests that “Comparative renditions of the same musical or other composition may be conveniently associated for reproduction. Thus the same song – ‘Annie Laurie’ for instance – may be recorded when sung as a solo on one side of the disk and when sung as a quartet on the other. Hamlet’s soliloquy as spoken by an English Actor might be recorded on one side of the disk, and the same soliloquy as spoken by a French actress (author’s italics) might be stamped on the other.”
Again, “…any composition too extensive to be recorded upon a single disk-face may be recorded in part on one such face, and in part upon the opposite face…”
Lastly, Petit makes another potentially valid point: “…the indentations on the under surface of the disc… heighten the frictional adhesion of the disk to the felt with which the rotating table of the machine is usually faced, and thereby decreases the necessity for special clamping means, and so facilitates the use of the record-disk in the reproduction of sounds.”
To sum up:
1. A double sided record would give more accurate pressings;
2. They would be uniform on both sides;
3. They would have less surface noise;
4. Each side would be far less costly to manufacture;
5. Besides ‘extended works’, ‘comparative recordings’ could be coupled;
6. Better adhesion between the record and the turntable.
For all the creative thought that went into the application, it was almost exactly three years before the U.S. Patent Office granted it on January 5th 1904. I have no idea why there should have been this long delay. Frederick Marion Prescott (1869-1923) had an interest in the patent, and I leave it to others who understand the complex ramifications of the early talking machine world (in which Prescott was already a veteran) to perhaps enlighten us a little.
It may be that this ‘daring’ patent was a method by which Petit – and Prescott – could control, or licence, the production of double sided discs for seventeen years, that being the term of a U.S. patent in those days. Such control would have been very lucrative indeed. However, as Frank Andrews has pointed out in several of his articles, the patent was soon overthrown, at least as far as Europe was concerned. In 1905 a court in Imperial Austria-Hungary found the Austrian patent ‘wanting in novelty’, and dismissed it. Such a valuable commodity was not lightly to be lost, and an appeal was lodged for its reinstatement. This too was dismissed in May 1906, more or less ending the story in Europe. The patent survived, however, for some time in the U.S.
I downloaded a .pdf file of the patent; it’s all public domain, so if you want you can get the pdf here .
An interesting byway into the history of disc recording, though!
Quite a lot of extra info. is also to be found if you Google around…
Page written 16th February 2012.
Re-formatted 18th December 2015.