326 Mr. W. Ellis on the Change of Rate produced in a Clock 



respect to the other magnet, giving four sets of observations. 

 Between each set and again at the completion of the observations, 

 the clock-rate was determined with the pendulum-magnet 

 only in position : these determinations of the clock's normal 

 rate were very satisfactory as respects steadiness of rate : the 

 changes produced by the action of the magnets on each other, 

 as exhibited in the following Table, may therefore be considered 

 (for the magnets used) very exact. When the adjacent poles of 

 the two magnets were similar, the effect of the repulsion retarded 

 the clock; when the adjacent poles were unlike, the effect of 

 the attraction accelerated the clock. In the following Table is 

 given the increase or decrease of hourly gaining rate for every 

 position of magnets and distance of magnets tried, with the cor- 

 responding total arc of vibration : — 



Distance 

 between 

 adjacent 

 poles of 

 magnets. 



Lower pole of fixed magnet. 



in. 



0-03 

 004 

 0-05 

 0-06 

 006 

 007 

 012 

 018 

 0-20 

 021 

 026 

 034 

 0-35 

 0-58 

 0-67 

 0-76 

 0-81 

 0-98 

 113 

 171 

 171 

 179 

 1-97 

 2-26 

 2-40 



s. 



N. 



N. 



S. 



Upper pole of pendulum-magnet. 



S. 



S. 



N. 



N. 



Increase of hourly gaining rate. 



-2-08 

 -2 : 04 



-178 



-1 : 43 

 -0-94 



+7-40 



+5-18 

 +410 



-2-42 



+ 2-84 



+ 1-58 



-0-59 



-0- 



+0-66 



-016 



+0-26 



+011 



202 



• 0-97 



■0-29 



Arc of vibration. 



Repelling 

 magnets. 



+51 



+272 



+216 



+ 102 



4 42 



4 44 



4 38 



4 49 

 4 49 



4 45 



+0-24 



4 44 

 4 37 



4 51 



4 4*3 



4 32 



4 42 



Attracting 

 magnets. 



4 11 



4 14 

 4 24 



4 26 



4 19 

 4 27 



4 33 

 4 37 



4 31 



4 42 



4 38 

 4 38 



4 34 



It is to be understood that the arc of vibration given in the 

 foregoing Table is the total arc reckoning from the extreme limit 

 of vibration of the pendulum on one side of the perpendicular 

 to its extreme limit on the opposite side. The amount of arc 

 when no magnetic action existed (that is, with the pendulum- 



