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L. On a Mechanical Violin-Player for Acoustical Expe- 

 riments. By C. V. Radian, M.A., Palit Professor of 

 Physics in the Calcutta University"". 

 [Plate XIV.] 



THE accompanying illustration (Plate XIY.) and brief 

 description of a mechanically-played violin which has 

 been developed after considerable experimentation and used 

 in a series of studies of the acoustics of bowed stringed 

 instruments may be of interest to readers of the Philo- 

 sophical Magazine. The apparatus has been designed to 

 reproduce as closely as possible the conditions obtaining in 

 ordinary musical practice. A violin and a horse-hair bow of 

 the ordinary type are used, and the object is to enable the 

 strings to be bowed with accurately controlled and mea- 

 surable pressures and speeds. Pressures ranging from one or 

 two orammes weight up to a hundred grammes or more, and 

 speeds ranging from one or two centimetres per second up to 

 •half a metre per second or more could be obtained and 

 determined. 



The arrangement differs from the ordinary playing of the 

 instrument in that the bow itself remains stationary and the 

 violin is caused to move to and fro with uniform speed. The 

 lio-ht wooden cradle on which the violin is mounted rests on 

 a brass slide which moves noiselessly to and fro along a 

 well-oiled cast-iron track. The necessary movement is 

 obtained as shown in the Plate by means of an endless chain 

 which carries a pin working in a vertical slot attached to the 

 brass slide. The chain is stretched taut between two free- 

 wheels and is kept in movement by the rotation of one of 

 the axles with fly-wheel and belt as shown in the Plate. 

 By using a conical driving pulley on which the belt runs, 

 various speeds of movement can be obtained. Very little 

 power is of course required to drive the apparatus, but in 

 order to obtain steady and uniform speeds over long intervals 

 of time, it is advisable to use a shunt-wound motor with an 

 ample margin of power running on little or no load in order 

 to drive the apparatus. No special speed regulation will 

 then be necessary. 



The mounting of the bow demanded special attention in 

 order that satisfactory results might be obtained. As can be 

 seen in the Plate, it is attached to the end of a long wooden 

 lath which is carefully balanced on an axle fitted with ball- 

 bearings in order to secure the necessary solidity and freedom 



* Communicated by the Author. 



