298 



NATURE 



juNt: 8, 1916 



one or two, in which the problem could be dis- 

 cussed with abundant accuracy simply by the use 

 of the geometric principle enunciated in text-books 

 in dealing- with the forms of the teeth of wheels. 



The development of the moving picture and its 

 mechanism, like that of many other inventions, 

 has had to wait for, and has stimulated invention in 

 relation to, its own elements or adjuncts. For 

 instance, the early workers ' in moving-picture 

 photography were met first by the insufficient 

 sensitiveness of the photographic plate. The wet 

 plate, with its silver bath, was, of course, hope- 

 less; but the dry plate, with all its advantages of 

 easy manipulation, has steadily improved in its re- 

 quirements of light to make a good picture, until 

 this has ceased to be a serious difficulty in a good 

 light. However, the glass plate itself limited the 

 number of pictures in a sequence to those that could 

 be arranged in a spiral on a disc, and so was 

 wholly inconsistent with the modern moving pic- 

 ture exhibition. The film, and with it the series of 

 devices for sensitising, developing, fixing, wash- 

 ing, and perforating, had to be created before the 

 moving picture as now understood could exist. 



Two other questions discussed are those of 

 colour kinematography, and living and speaking 

 pictures. The explanation of the two methods of 

 obtaining the three-colour components, the one by 

 addition and the other by subtraction, is exceed- 

 ingly clear, and this makes the discussion of the 

 methods of different inventors the more luminous. 

 Some stress is laid, and rightly so, on the Urban- 

 Smith two-colour method, patented in 1902, which 

 is the basis of the popular kinemacolour. The 

 author does not state that this patent was the 

 subject of an action which was hotly contested as 

 far as the House of Lords, when a judgment was 

 delivered which is of the most drastic kind in 

 relation to ambiguity and confusion of language 

 in a specification. This judgment is now con- 

 stantly quoted, and is one which was much needed 

 in consequence of the improper use of English 

 patent protection, made more especially by Ameri- 

 can and German patentees. While there was no 

 dishonest intention of this kind exhibited in the 

 specification in question, there is no doubt that our 

 Patent Office has been induced to allow patent 

 specifications to be issued which are designed to 

 mean anything in emergency, to the great advan- 

 tage of the big bully; and, thanks to a kinema- 

 colour specification, w-e now have in a judgment a 

 cure so drastic as possibly to be more dangerous 

 to the honest inventor than the disease. 



In the speaking picture not only is the moving 

 picture projected, possibly in colour, but the 

 sounds heard at the time at which it was taken are 

 reproduced also. When it is remembered how 

 quick the eye and ear are to p>erceive want of 

 synchronism, it will be realised what the mechani- 

 cal difficulties are that must be surmounted in pro- 

 ducing a successful speaking picture. Those who 

 had the good fortune to be present at the Royal 

 Institution when the Gaumont speaking pictures 

 were exhibited in 191 3 will remember how per- 

 fectly every element separately, and the whole 

 conjointly, were produced. Of the colour effects 



NO. 2432, VOL. 97] 



the most astonishing were those of butterflies, with 

 those brilliant iridescent blues and purples which 

 would seem to defy imitation. However, after 

 the photograph of those butterflies mounted on 

 clockwork stands so as to revolve slowly had 

 been shown, the originals on their stands were set 

 revolving on the table, and it was seen that as 

 far as the memory would serve the succession of 

 iridescent hues, caused by the changing aspect of 

 the wings, was identical in the original and in its 

 presentation on the screen, and it appeared that 

 Clerk Maxwell's three-colour theory of colour vision 

 could not have a better proof of its sufficiency. 

 However, the butterflies did not speak. Other pic- 

 tures, one of a cock crowing, another of lions in a 

 cage being annoyed by a bar of iron which was 

 allowed to drop on to the stone floor, were each 

 achievements of so perfect an order that, so far as 

 the experience of the present writer goes, no 

 moving picture had been so equable and free from 

 flicker ; no colour picture, whether moving or not,, 

 projected on the screen had approached these in 

 faithful accuracy of colour ; no gramophone — ex- 

 cept, perhaps, the Autexophone of Parsons — had 

 given so faithful a sound record ; and the combina- 

 tion of the whole and the exact synchronism were 

 such not only that the motion of the cock agreed 

 with his voice, but the clink and ring of the iron 

 exactly agreed with the moment at which it was 

 seen to strike and bounce from the floor, while the 

 lions were keeping up a snarl in consonance with 

 their features. Where so much was attempted a 

 failure in any part, and above all in the synchron- 

 ism, would have converted the feeling of amaze- 

 ment and delight experienced by the audience into 

 one of disgust at the obvious sham of the whole 

 thing. 



In addition to the list of patents to which refer- 

 ence has already been made, there is a bibliography 

 covering the period from 1825 (Roget) to 1914 

 (Hallberg), and a list of British and foreign perio- 

 dicals devoted to the subject. 



C. V. Boys. 



MODERN ANALYSIS. 



A Course of Modern Analysis. By Prof. E. T. 

 Whittaker and Prof. G. N. Watson. Second 

 edition, completely revised. Pp. 560. (Cam- 

 bridge : At the University Press, 191 5.) Price 

 18.9. net. 



J^HE treatise now under notice, which appears 

 as a second edition of a former treatise by 

 one of the authors, is in all essential respects a 

 new work. Its scope has been extended in many 

 directions, and very recent developments, of 

 which a substantial number are due to the authors, 

 receive a fair share of attention. The volume 

 now gives a somewhat exhaustive account of the 

 various ramifications of the subject, which are set 

 out in an attractive manner. An unusually com- 

 plete set of references is included, and the book 

 should become indispensable, not only as a text- 

 book for advanced students, but as a work of 

 reference to those whose aim is to extend our 

 knowledge of analysis. The references to original 



