Category Archives: Claude Hamilton Verity

The Veritiphone system

I have previously written three posts on the efforts of the Leeds inventor Claude Hamilton Verity to develop a synchronisation system for motion pictures using a sound-on-disc system. In 1923 he sailed to America to work with the Vitagraph Film Company, though the result of this collaboration remains unknown. His efforts were reported worldwide but he has disappeared from the history of British cinema. You can read my earlier posts here, here, and here.

I had not thought about Verity for many months until Luke McKernan asked me a question yesterday, and I took the opportunity to have a quick search to see if anything new was available.

Rather wonderfully I have just found a discussion at Gramophone Collecting which has images of two articles. One is by Verity himself written for The Sound Wave 1922 describing his ‘Veritiphone’ system complete with a picture of this unusual machine.There is even a picture of the man with his machine. The other is a description of his efforts.

The original discussion can be found here.

The introduction to the article reads:

We have had an opportunity of testing the acclaimed merits of the Veritiphone. This is the invention of Mr. Claude H. Verity, of Leeds, who has made a deep study of the synchronisation of moving pictures, and who has admittedly accomplished what at one time appeared to be an impossible feat, that of timing the movement of the lips of the speaker  with the recorded speech given coincidentally. The Veritiphone is, indeed, the outcome pure and simple of Mr. Verity’s pursuit of the science of synchronisation.

From this we can infer the Veritphone system worked, performing exactly as Verity claimed and as reported around the world. And yet he is utterly unknown to historians of British cinema.

Here are the images from the forum.

Claude Hamilton Verity III

I have drawn attention to the Leeds inventor Claude Hamilton Verity and his efforts to develop a sound-on-disc system for the synchronization of image and sound in two earlier posts that can be accessed here and here. This week I bring to your attention some other references to Verity I have come across recently.

First, an article by Frank H. Lovette and Stanley Watkins, titled ‘Twenty Years of “Talking Movies:” an Anniversary’ and published in the 1946 volume of Bell Telephone Magazine, refers to Verity as someone who made a notable contribution to the development of talking pictures alongside such illustrious names as Thomas A. Edison, Pathé Freres, Leon Gaumont, and Orlando E. Kellum. The article can be accessed here.

The authors clearly do not take The Jazz Singer in 1927 to be point at which pictures began to talk, and instead choose as their starting point the demonstration of the Vitaphone system on 6 August, 1926, for the screening of Don Juan, starring John Barrymore. This is unsurprising given that Bell was itself involved in the development of this system, but they do describe this screening somewhat poetically:

Before the applause could die away, the dramatic sequences of Don Juan unfolded against their synchronized musical background. Scientists, public officials, prominent figures from many walks of life sat in amazement until the last crescendo and finale of this scientific marvel. The men who brought it into being by their refinement of existing arts were hailed as having made possible “the greatest invention of the twentieth century.” And Dr. Michael I. Pupin was led to exclaim that “no closer approach to resurrection has ever been made by science.” The pioneers of Western Electric and Bell Telephone Laboratories and their collaborators of Warner Brothers and Vitaphone experienced that night a measure of accomplishment which few men of science ever live to taste or see.

We can forgive the authors a touch of hyperbole when writing about Bell-developed technology in a Bell-funded journal, but this raises an interesting question about when we should date the earliest successful demonstration of synchronized sound in cinema. There were other inventors to successfully demonstrate the synchronization of sound and image prior to 1926, including Kellum’s Photo-kinema system and Verity’s system both of which were demonstrated in 1921. D.W. Griffith used the Photo-kinema system for Dream Street, which premiered on 2 May, 1921, with two sound segments; and we have reports of the demonstration of two original shorts produced by Verity in Harrogate on 30 April, 1921 (see the first link above). We also know that in November 1923, Verity sailed to New York to meet with J. Stuart Blackton of the Vitagraph Film Company and gave an interview to The New York Times regarding the synchronization of sound and image in January 1924 (see the second link above). We do not know what impact Verity’s work in England had – if any – on the development of ‘the greatest invention of the twentieth century.’

The article refers to Verity’s system as Veritiphone, but this term appears only infrequently in other articles.

Second, two articles in the Wellington Evening Post from 1921 and 1923 refer to Verity’s efforts. These articles are available from Papers Past at the National Library of New Zealand, and rather wonderfully, they can be reproduced under a creative commons licence.

The first article was published on 3 June, 1921, and is largely a direct quote from an earlier article published in The Daily Mail. I have not found this earlier article, but given the timing I assume that the demonstration referred to was the one that took place in Harrogate in April 1921.



Talking kinema films, it is claimed, have definitely advanced a stage as ‘the result of the invention of a synchroniser by Mr. Claude H. Verity, a Harrogate engineer. With this instrument in the projector-box, it is stated, an operator, by simply sliding a knob quite independently of watching the screen, can work synchronisation to 1-24th of a second.

In a Harrogate building where secrecy has been maintained for nearly five years of experimenting, writes a correspondent to the London Daily Mail, who has witnessed a straight drama and cross-talk comedy exhibited in conjunction with a gramophone. “There was no mistaking the accuracy of voice and lip movement. If it should vary a tenth of a second it would be due to the fact that the actors were so much out in repeating for the gramophone recorder what they had done for the screen. These processes are separate and are linked up by an expert stenographer.

“The synchroniser does away with the necessity for stopping the action of a picture to introduce worded explanations; indeed, dialogue becomes a distinct part of the picture.

“For operas with singing and music a child could work it because there is a fixed tempo. Should the film break the speaking can be stopped and taken up again.”

A great advantage of the invention, it is urged, is that with the apparatus in projecting-boxes the synchronised film could be circulated in the ordinary way.

The two films referred to above would be The Playthings of Fate (the drama) and A Cup of Beef Tea (the comedy). I would assume that this is the first time the term ‘cross-talk comedy’ is used in reference to the cinema.

The second article was published on 1 September 1923, and is only a passing reference to Verity as part of a much larger piece.

Synchronization of the film and its musical counterpart seems to be solved by the “Veritphone,” an invention of Claude H. Verity, of Leeds, England. It aims at the alliance of sound and movement by the combination of a double set of “super-gramophones,” and an ingenious indicator, which shows when the film and the sound record are together.

Details of Verity’s patents that give a more detailed explanation of how the system worked can be accessed in my earlier posts.

Third, and slightly confusingly, there is another reference to Verity derived from an article published in The Daily Mail in De Sumatra Post published on 11 November 1922. I have no idea what this says because it is in Dutch. The complete issue of De Sumatra Post can be downloaded as a pdf file here (it’s about 7.1 MB and I think it is from the Dutch equivalent of Papers Past), and the short piece referring to Verity is at the bottom of page 14.

Fourth, a notice in The Electrical Review 90 1922: 416 announces the successful demonstration of Verity system at the Albert Hall in Leeds in 1922 (the date is given as 3 March whereas other articles give the date as 3 April), noting that

By experiment over a considerable time past, Mr. Verity has provided an apparatus which certainly yields co-timing of the lip movements of the persons on the screen with the sounds emitted from the electrically-controlled gramophone, …

By the time of his 1922 demonstrations, Verity had spent at least 5 years and (by his own estimation) some £7000 of his own money developing his synchronisation system.

Finally, and a good deal less wonderful than anything from New Zealand, is a reference to Verity in an article published in Political Science Quarterly in 1948. The full reference is Swensen J 1948 The entrepreneur’s role in introducing the sound motion picture, Political Science Quarterly 63 (3): 404-423. I do not know how this piece refers to Verity – it may be only as a name in a footnote, possibly derived from the Bell Telephone Magazine article referred to above – because the article lies behind a paywall at JSTOR. There is no good reason why an article from 1948 should be behind a paywall in 2011.



Claude Hamilton Verity in New York

I have written about Claude Hamilton Verity, an inventor from Leeds, and his efforts to develop a commercially successful synchronization between sound and image before (see here). This post follows up on Verity’s trip to America, and looks at his efforts through his own words.

On 9 November, 1923, Verity set off for New York aboard the Aquitania from Southampton, and on arriving declared he was meeting the vice president of the Vitagraph film company, J. Stuart Blackton. Verity’s purpose in traveling to America was to promote the synchronized moving pictures he had demonstrated at Harrogate in 1921 and London, Leeds, and Bradford in 1922.

On 20 January, 1924, the New York Times published an article comprised largely of Verity’s pronouncements on the future of the sound film. If you want to read the article in full you will, I’m afraid, have to pay (about $4); but you can also find this article in The New York Times Encyclopedia of Film, 1896-1979.

Verity’s pronouncements cover three topics: the need for the sound film to reinvigorate the interest of audiences, the prospects for the sound film, and the technical difficulties of the sound film and Verity’s attempts in overcoming them.

Verity first remarks on the fact that audiences, as far as he is concerned, are wearing of the silent films, as its novelty has long since worn off:

Personally, I believe that music carefully edited and synchronized with the pictures adds greatly to the enjoyment of the production. And I really believe that the public is losing interest in the silent film – it maybe gradual but nevertheless I believe it is true.

To explain this loss of interest, Verity points to the varied nature of the programme provided by exhibitors, including musical interludes, and singing and dancing acts as proof that audiences needed some other entertainment alongside a silent film. He also goes onto point out that this fine for moderately-sized theatres large towns and cities where, exhibitors can afford to put on such additional entertainments, but that this is scarcely possible in the more numerous smaller establishments that he describes as the ‘backbone of the industry.’ The need for sound, then, is a matter of maintaining audience interest in the medium of cinema, especially as everything else appears to have been tried:

Producers have exhausted nearly every conceivable subject; they have clothed their artists in elaborate costumes and presented them with almost nothing on.

Despite the fact that he spent so much of his time and own money on developing devices for the synchronization of sound and image, Verity seems to be ambivalent about their prospects. On the one hand, he thinks that there is a ‘great future’ in the synchronized picture and that pictures synchronized with sound, ‘be it voices or music, will enhance the worth of productions;’ while at the same time, he states that ‘I don’t think that talking and singing pictures have really much entertainment value.’ This is, I think, an odd opinion for some one who claims to have spent some £7000 on his own inventions for precisely this purpose (see here), but then many inventors fail to realise the potential of their devices because they view the problem from a purely technical standpoint. The synchronization of sound and image was a technological puzzle, but it took a showman to really make it work. Sound pictures, would Verity states, lead to new interest in films with the recording of music hall acts, sketches, and songs, but he sees it only as a means of recording existing acts and not of creating something new; and the principle beneficiaries would be the legion of small theatres that cannot attract such acts and can, therefore, substitute for them, with a film.

The second half of the article is comprised of Verity discussing the technical problems of the sound film, but his first statement in this area is an intriguing plea for government investment in potential technologies.

The history of almost all discoveries reveals how fate clings to the secrets stored up for the future welfare of mankind. Progress is ever slow. Inventors carry on their lonely and strenuous efforts secretly, and nearly always under the greatest financial difficulties. The state should alter this so that when an inventor could prove before an appointed commission that he had practical ideas, which, if developed, would be to the general welfare of the community at large, he could receive laboratory facilities or financial assistance.

Such a scheme would immediately cut venture capitalists out of the picture with the state holding the rights (in some form) to patents and would therefore never happen; but this argument provides an insight into Verity’s own position as an inventor. Born into a family of hardware merchants in Leeds, Verity produced a range of inventions and held a series of patents but he never worked for a large corporation and appears to have met the expense of development from either his own pocket or from the profits of the family firm. We know from Douglas Gomery’s research on the history of sound technology that the major corporations with the large research laboratories (Western Electric, General Electric, Radio Corporation of America, and so on) along with the major Hollywood film studios (Warner Bros., Fox) successfully introduced synchronized pictures at the end of the 1920s. In Verity we have a skilled and creative inventor, but one who also epitomizes the British tradition of the ‘practical man’ working alone his shed – that said, as a lone inventor he has achieved much, getting to New York to meet with the vice president of the Vitagraph film company. Verity’s trip to New York at the end of 1923 comes just before Warner Bros. purchases Vitagraph (in 1925), and begins turning out Vitaphone sound shorts using a sound-on-disc system. Verity’s patents for sound cinema from 1916 to 1929 all relate to sound-on-disc systems, and it would be interesting to discover what, if anything, Vitagraph learned from Verity or if (and why) they thought his invention unworthy. Verity went to the trouble of traveling over 3000 miles to meet Blackton, and Blackton went to the trouble of meeting Verity, so each must have expected something from this meeting. It would be fascinating to know if either of them got it. It would also be fascinating to know who else Verity was meeting with, but the New York Times article refers only to his being ‘in the city for several weeks.’ (The Ellis Island immigration records list his intended stay as 3 months, so the article was published at the end of this period). Verity is dismissive of the film industry, so perhaps he found it to be a wasted trip:

It stands to reason that the vested interests in the screen are not particularly anxious for the success of the synchronized film, but I think when a commercial solution is actually found they will fall over one another to obtain its actual control.

It is also interesting to note that there is a break in the patents filed by Verity in the UK for sound film devices from 1922 to 1928. Perhaps he found his New York trip to be particularly discouraging, as his swipe at ‘vested interests’ would indicate.

Verity refers to his various attempts to produce synchronized films. The first attempt he refers to only to say that it was ‘too complicated,’ but gives no other details. The second attempt he refers to was a sound-on-disc system that would provide a ‘commercial solution.’ Verity states that this system has been successfully demonstrated in England several times, and is presumably the device demonstrated at Harrogate in 1921. This ‘second attempt’ is almost certainly the device described by the 1916 GB patent and the 1917 US patent and later improved on the early 1920s. (See here and here for details on Verity’s patents and how to access them). It would seem obvious that it is these patents that Verity has traveled to New York to discuss with Vitagraph. The ‘Verity system’ operated by recording the sound separately from the images, and then providing the projectionist with the sound and the disc and a mechanism that would allow him to keep the two in synchronization to within 1/25th of a second by adjusting the variable speed of both devices according to an array of lights that represents their relative speeds.

Although, Verity states that his system ‘never once failed,’ he admits the need for a new device that will enable for sound to be ‘synchronized on the same film’, and claims that his third attempt has provided a solution to this problem.  He is, however, somewhat sketchy on the detail here, and it may be that an idea had suggested itself to him after the meetings in New York. The impetus behind this ‘third attempt’ appears to have been frustration with projectionists who could not follow the instructions for the Verity system and thereby let the film get out of synch – cuttingly he remarks that while the technology ‘never once failed,’ ‘it is human nature to fail at times to work according to instructions.’ This is, of course, perfectly true, and if sound film had been dependent upon the skill of the projectionist it may have failed due to the variability in the quality of the show from one theatre to another. Sound-on-film was an advance on sound-on-disc for many reasons, not least because it removed human error from the exhibition of motion pictures. Sound-on-film would also mark an improvement, in Verity’s opinion, for shooting on location as this would allow for the simultaneous recording of sound and image. He notes that a sound-on-film system would present considerable difficulty in editing down the 50000 feet of film shot to the 8000 of a feature, but then at no point does he ever seem to express any understanding of the process of editing (or any other production practices) and so his calim to have solved this problem is perhaps dubious. In Verity’s patents there is no mention of a sound-on-film system, and his patents from the late-1920s all relate to improvements for sound-on-disc systems, and one patent which refers to a method of synchronizing films with wireless broadcasts (notably after Logie Baird, Marconi, and Farnsworth). We can therefore conclude that this ‘third attempt’ was not realized – certainly not in form suggested by this interview. Nonetheless, he signs off by stating that ‘inventors are having a race in various parts of the world hunting for the true solution of the synchronized picture. I believe that at last I have found it.’

Claude Hamilton Verity

This post introduces some facts and resources about the life and work of Claude Hamilton Verity, and engineer from Leeds, whose work on synchronous sound in the cinema deserves far greater mention that it gets (in histories of British cinema in particular). Included are some basic facts, some references to where Verity does appear in research on film, patents to Verity’s sound technologies, and some contemporary pieces that refer to Verity’s work.

Claude Hamilton Verity was born at Leeds in May 1880, the youngest child of Edwin and Ann Verity. Edwin Verity was an ironmonger with a workshop at . Edwin was one of the Verity Brothers who had a large premises on The Calls by Leeds Bridge. Edwin later took premises round the corner at 168 & 169 Briggate as a hardware merchant. It was these premises that Claude was later to use as his workshop, and are now Bar Fibre. These premises are also located approximately 200 metres from the building at Leeds Bridge, where Le Prince shot his footage of traffic at the Corner of Briggate, Swinegate, and The Calls.

Claude was brought up in Roundhay in the north of the city – an affluent part of Leeds that was also home to Louis le Prince and the Whitley family in the 1880s. The 1901 census has Verity listed as a student at a College of Agriculture and resident at Downton, Wiltshire. He also seems to crop up in Seacombe, nr. Liverpool, as an engineering draughtsman c.1910, and there is an engineer called Claude Hamilton Verity living in Scarborough in 1912, who is presumbaly the same person. He later moves to Harrogate (where his mother’s family were from), and then Harpenden, Hertfordshire.

Verity held many patents, including improvements to stoves, revolving doors, electric radiators, clouderising coal dust, low-temperature carbonisation, and ‘apparatus for the inhalation of medicated vapours.’ All of this suggests that he was a skilled engineer, who could turn his hand to many different things. There is also a book published in 1928, titled Industrial Prosperity, and authored by a Claude H. Verity, but I have not yet confirmed the identity of the author. It is Verity’s patents in the synchronising of sound and pictures that are of main interest to film scholars, and the following is a chronological list of the relevant patents:

  • The synchronisation of machines for recording and reproducing sounds & movements. GB103407, Verity, C. H. May 11, 1916.
  • Synchronization of Machines for Recording and Reproducing Sounds and Movements. Claude Hamilton Verity, of Leeds, England.  No execution date.  Filed May 23, 1917, Serial No. 170,531.  Classification 352/23. This is a US patent.
  • Synchronisation of machines for recording and reproducing sounds and movements. GB165489, Verity, C. H. Jan. 28, 1920.
  • Improvements in or relating to gramophones and like sound reproducing machines. GB207222, Verity, C. H. July 21, 1922
  • Synchronisation of machines for recording sounds and movements and for reproducing such sounds and movements by phonograph and kinematograph. GB318847, Verity, C. H. June 5, 1928.
  • Apparatus for reproducing synchronously recorded disk records and kinematograph films. GB318688, Verity, C. H. June 19, 1928.


Figure 1 Verity’s registration marks for resynchronising cut sound film (GB318688)

  • Means for the synchronisation of broadcast wireless sounds and kinematograph films. GB320881, Verity, C. H. July 23, 1928.
  • Improvements relating to the synchronous reproduction of picture films and disk sound records. GB321624, Verity, C. H. Aug. 13, 1928.
  • Improvements relating to phonograph disc recording & reproducing machines and means for driving and synchronising same with kinematograph apparatus. GB322561, Verity, C. H. Sept. 24, 1928.
  • Improvements relating to electric pick-up supports for gramophones and means for indicating the position of the needle in the record groove and to facilitate synchronous reproduction with picture projection. GB324411, Verity, C. H. Oct. 22, 1928.

Most of these patents relate to sound-on-disk systems, but Verity’s appears to have adopted an approach that is less dependent upon the technology and focuses more on the operator’s problem of keeping sound and image together. It’s a very human approach to a technological problem : for example, the 1920 patent for the  Synchronisation of machines for recording and reproducing sounds and movements uses two rows of lamps to indicate when the operator has achieved the union of sound and image by manipulating motors to bring the projector and the sound mechanism together, and which will tell the operator when they start to go out of synch.

Verity’s work attracted international attention: one newspaper report from 1922 talks about a German patent, but I haven’t been able to find this; while Verity was crossing the Atlantic to work with the Vitapgraph Company in New York. Altman (1992) mentions Verity’s arrival in New York and his demonstration of the synchronisation of music and talking pictures


Figure 2 The Ellis Island register shows Verity was met by the vice-president of the Vitagraph Co. as he disembarked from the Aquitania in 1923.

From reports in the local Yorkshire press, Verity’s system worked well and was popular. Verity apparently first demonstrated his talking pictures at the Royal Hall Theatre in Harrogate on 30 April 1921, before moving to London in June/July 1921, and then at the Albert Hall, Leeds in the first weeks of April, 1922.

A contemporary description gives an indication of how image, music, and dialogue were brought together.

Leeds Mercury, 27 June 1921



The latest development in singing and talking pictures was explained at a demonstration on Saturday at the Philharmoinc Hall, London.

The inventor, Mr. Claude Verity, of Leeds, claimed to be able to synchronise perfectly the spoken word and the lip movements by the players shown on the screen.

By Mr. Verity’s system it is claimed to be possible to synchronise speeches, sounds, music, or anything that is at present being done at any of the London theatres – opera, drama, musical comedy, or revue. The inventor does not do away with the orchestra; his object is to synchronise the spoken word or song, the orchestra accompanying the gramophone while the movements are thrown on the screen.

The two productions shown on Saturday, ‘A Cup of Beef Tea’ and ‘The Playthings of Fate,’ proved that the invention has great possibilities.

The public interest in talking pictures can be gauged from this announcement of Verity’s 1922 shows in Leeds, which gives the size of the audience for the initial Harrogate run.

Yorkshire Evening Post, 3 April 1922



Mr. C.H. verity, the inventor of the apparatus which has made the synchronisation of film and gramophone a practical proposition, is the head of a Leeds firm of hardware manufacturers and merchants. He is presenting his talking and singing pictures at the Albert Hall, Leeds, this week. Entertainments will be given each evening, and on three afternoons. The programme consists of the first film productions under the Verity system of synchronisation.

Mr. Verity claims that the cost of these productions will be no greater than that of the majority of silent films, because it is cheaper to help out scenes and actions by words than by the multiplication of dumb show. There are interesting possibilities in the production of talking pictures in these days when the demand is all for novelty and originality in entertainment. Four performances recently given in Harrogate attracted over 5600 people.

As another report indicates, the road to the synchronisation of sound and image was long and expensive, and it is important to remember that Verity was not a research scientist for a large corporation but ran a hardware manufacturers in the centre of Leeds.

Yorkshire Evening News, 1 April 1922




Mr. Claude H. Verity, the Leeds inventor, is making a bold bid to enlist the sympathies of the public in his talking and singing pictures. He claims that he has definitely and absolutely solved the problem of the synchronisation of the voice with the picture on the screen.

For over three years he has been perfecting his idea, and so fa it has entailed a cost of £7000, but now to quote his own words: ‘With my system of synchronisation I can guarantee to keep this relation of sound and lip movement under synchronous control to within one-twenty-fourth of a second for any length of time.’

Next week at the Albert Hall, Leeds, the local public will have its first opportunity of judging the merit of the invention.

The solving of the problem of synchronisation was proved and admitted by the critics at Mr. Verity’s first trade show in Harrogate. There was criticism, Mr. Verity says, not in regard to the question of synchronisation, but in regard to the sound productions of the gramophone used.


Mr. Verity has given many trade shows in various parts of the country, and never once has his claim to have solved the synchronisation problem been doubted. The only thing he needs he points out, is what might be termed a super-gramophone, and in this connection it may be stated, Mr. Verity has gone some way to meet this need.

By the means of electric amplification and a new design of gramophone horn, the inventor ensures that the spoken word is clear and easily distinguishable.

Very shortly a company is to be formed, and with the necessary financial backing the invention should not fail to succeed.

Mr. Verity claims that everything in the way of singing or speaking can be synchronised by means of his method. He also wishes to make it clear that he does not intend to work on the lines of a monopoly in regard to his invention.


Mr. Verity does not suggest that the whole programme in all the countless picture-houses should be entirely devoted to ‘talking pictures;’ he introduces the idea with a view to an enjoyable variation in the programme.

The ‘Yorkshire Evening News’ is able to add that Mr. Verity has now had his ‘talking-picture’ idea patented in Germany. This is itself proof that he has not encroached on any previous idea on this point. The German system of granting patents is different to the British system.

Here a patent is granted after a search through British patents only; in Germany the patents of all nationalities are first scrutinised.

For all this effort, Verity does not get much of a mention in histories of British cinema, but he is mentioned on occasion. As noted above, Altman (1992) mentions Verity’s visit to the US and he features in The New York Times Encyclopedia of Film (1984),  which suggests that there are references in the New York press to the demonstrations of the Verity system. There is also a reference to Verity’s trip to New York in Gramophone in October 1926, albeit a reference that is inconclusive (I haven’t found the original report):

The problem of synchronizing films and records has been solved if we are to believe the reports of the demonstration of the Vitaphone in New York. There is an excellent and full account of the problem and of the solution in the Wireless World for September 15th. Three years ago we reported the departure of Mr. Claude Verity, who was experimenting in the subject, for America ; but it is not said whether he is at the bottom of the Vitaphone. It is the Western Electric Co.’s patents which have made the synchronization possible, worked in conjunction with Warner Brothers’ Pictures Inc (22).

Verity is also mention by M. Jackson Wrigley (1922: 115-116), who refers to the ‘invention of a synchronizer by Mr. Claude H. Verity, a Harrogate engineer, enables the operator, by simply sliding a knob, quite independently of observing the screen, to work synchronization to 1-24th of a second.’


Altman, D. (1992) Hollywood East: Louis B. Mayer and the Origins of the Studio System. New York: Carol Publishing Group.

Jackson Wrigley, M. (1922) The Film: Its Use In Popular Education. London: Grafton.

The New York Times Encyclopedia of Film, edited by Gene Brown New York: New York Times Books, 1984