REVIEWS 683 



We are pleased to note that the Swiney Prize was at once awarded to this 

 book. We warmly congratulate Dr. Mercier on this well-deserved honour, which 

 he has now won for the second time. 



Hugh Elliot. 



On the Mechanical Theory of the Vibrations of Bowed Strings and of 

 Musical Instruments of the Violin Family, with Experimental 

 Verification of the Results: Part I. By C. V. Raman, M.A. Bulletin 

 No. 15, The Indian Association for the Cultivation of Science. [Pp. iii + 

 158.] (Calcutta: 1918. Price 3^. 4^. net.) 



Helmholtz on an experimental basis was able to construct a partial theory of 

 the bowed string. F. Krigar Menzel and A. Raps photographed, upon a revolving 

 drum carrying a film, various points of bowed strings so as to exhibit their 

 displacement-time graphs. E. H. Barton and his pupils took simultaneous 

 photographs of the behaviour of the strings and either bridge, belly, or air of a 

 monochord or violin. But in none of the foregoing cases was a direct mechanical 

 theory of the string, bridge, etc., attempted. This is now done by C. V. Raman. 



The equations of motion of the string are written and solved for the case of 

 a periodic force applied transversely by the bow at any given position. The 

 equations of motion of the bridge are next written and dealt with. The modus 

 operandi of the bow is afterwards examined and a simplified kinematical theory 

 of the bowed string is based upon it. This leads to a number of types of 

 vibration — two-step, three-step, etc., zig-zag motions appearing in the corre- 

 sponding graphs. 



Another interesting subject here treated is that of the effect of the mute, 

 which, by loading the bridge, enfeebles and veils the tone of the instrument. 

 For the purpose of these tests, loads were placed at various positions on the 

 bridge and simultaneous curves obtained photographically of the bridge and of 

 each of the strings in turn. The instructive results so obtained are given in two 

 plates. 



Photographic reproductions are also given of simultaneous vibration curves of 

 the belly and G-string of a violoncello when played at and near the " wolf-note" 

 pitch, showing alternate cyclical variations of amplitude. 



Other points dealt with are the effects of the variation of pressure and speed 

 of bowing and the relation between them, the width of the bowed place, the 

 yielding of the bridge, and the vibrations obtained from a 'cello by plucking 

 the strings. 



This work contains twenty-eight figures in the text and twenty-six excellent 

 full-page photographic reproductions, and well deserves the careful attention of 

 those interested in such a notable contribution to an important subject. 



E. H. B. 



Life and Letters of Joseph Black, M.D. By Sir William Ramsay, K.C.B., 

 F.R.S., with an Introduction by F. G. Donnan, F.R.S. [Pp. xix + 148.] 

 (London: Constable & Co., 1918. Price 6s. 6d. net.) 



Two books in one. A brief memoir of Sir William Ramsay, and a longer account 

 of the life of Joseph Black. The latter is an instance of the truth that only a busy 

 man can find time to do extra work. Sir William Ramsay was a very busy man, 

 but he could find time to write this excellent biography of Joseph Black, which 

 is also a history of an important period in chemical discovery, and could not have 



