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XVIII. On certain Modifications of a Form of Spherical 

 Integrator. By Fkedeeick John Smith, B.A. Oxon* 



WHILE working at the subject of Dynamometric Measure- 

 ments, a great number of different forms of mechanical 

 integrators were attached to a transmission -dynamometer 

 (Phil. Mag. vol. xv. p. 87). In one of these the small disk 

 of a Morin integrator (Phil. Mag. vol. xvii. p. 59) was 

 replaced by a sphere carried between four little cylinders ; 

 the sphere was made of phosphorbronze (Ashmol. Soc. 1884). 

 As long as the dynamometer was driven with but little 

 variation, the results were satisfactory; but as soon as one had to 

 deal with quick variation, either of tension of belt or of velocity, 

 it was found that the moment of inertia of the sphere was a 

 serious obstacle to accurate results. It appeared probable that 

 no instrument dependent upon the action of gravity could be 

 relied upon. This being the case, it was evident that if a 

 sphere was to be used it ought, in the first place, to be as light 



Fig. 1. 



as practicable and, secondly, as firmly held as possible from any 

 slip. These two ends have been arrived at as follows : — The 

 sphere Q is made hollow in order to be light, and it moves 

 between six wheels ; of these, four wheels, DEFG (fig. 1), are 

 * Communicated by the Author. 



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