THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOUKNAL OF SCIENCE. 



[FIFTH SERIES.] 



FEBR UARY 1882. 



X. On Integrating and other Apparatus for the Measurement 

 of Mechanical and Electrical Forces. By C. Vernon Boys, 

 A.M.S.M., Demonstrator of Physics in the Normal School 

 of Science, South Kensington* '. 



[Plates m., IV.] 



WHEN in February of this year I described my first 

 integrating-machinef before the Physical Society, I 

 felt that, unless the tangent principle could be so applied as 

 to admit of an indefinite growth of the integral, such principle 

 would be useless for practical purposes. In that machine the 

 integral is determined by the position of a cart, and so is 

 limited by the size of the apparatus. Since that time I have 

 devised a variety of methods of applying the tangent prin- 

 ciple in which the integral is determined by rotation, and so 

 there is no limit to the extent to which the integral may grow. 

 In the followiug paper, which is divided into two parts, I have 

 given in the first a description of a variety of integrating- 

 machines, while in the second are some useful applications of 

 the most simple form of integrator described in Part I. 



Part I. 

 At the present time there seem to be three types of inte- 

 grating-machines : 1st, those that may be called radius 



* Communicated by the Physical Society, having been read at the 

 Meeting on November 26, 1881. 



t Phil. Mag. May 1881. 

 Phil Mag. S. 5. Vol. 13. No. 79. Feb. 1882. H 



