22 Wilde, Evolution of tJie Mental Faculties. 



5. The times of descent of the smaller weight in 

 experiments 5 and 7 are the same as those in 2 and 4 with 

 the larger weight, in which, for the same height of fall, 

 the number of revolutions is doubled respectively. This 

 result is decisive as against the arguments brought forward 

 by Maclaurin and others to explain away the Leibnitzian 

 measure of moving force by substituting the element of 

 time for the space through which a moving body acts. 



Another demonstration of the absurdity of measuring 

 the momentum of a moving body by its mass and velocity 

 conjointly, is, by a method of equals, applied to the case of 

 four gyroscopes of precisely similar construction to the 

 one described. Let, therefore, four such instruments be 

 set in motion simultaneously by the fall of four weights 

 of 05 lb. each through a space of 30 inches, to generate 

 194 revolutions of the discs per minute, as in experiment i 

 in the Table. It will readily be allowed that there are 

 here four units of body and four units of motion according 

 to the definitions of Descartes and Newton. If now a 

 fifth similar gyroscope be set in motion by the fall of a 

 weight of 2 lbs. through the same space of 30 inches, the rate 

 of descent of this weight will be double the rate of descent 

 of the weights of 05 lbs., and will, consequently, generate 

 a double velocity of rotation, or 388 revolutions of the 

 disc per minute, as in experiment 2 in the Table. Hence 

 the quantity of motion in the disc, rotating with a double 

 velocity, is equal to the sum of the motions of the other 

 four discs rotating simultaneously with half the velocity. 

 But the quantity of motion in two of the discs, according 

 to Descartes and Newton, is equal to the motion of one 

 disc rotating with a double velocity, which is absurd ; 

 therefore, the force of a body in motion by the free 

 action of gravity is as the square of the velocity. 



Another obstacle which operates at the present time 



