XXVIII PHILOSOPHICAL SOCIETY OF WASHINGTON. 
THE KINEMATIC HYPOTHESIS. 
That motion is persistent is the kinematic hypothesis. In the 
early history of research many modes or varieties of motion were 
directly observed. To account for these motions they were said to 
be caused by forces, and Force was sometimes defined as that which 
produces motion. Something, therefore, was conceived to exist— 
not matter, not motion—an existence that would produce motion. 
Then arose the question, What is Force—this antecedent of Motion? 
The researches inaugurated from this standpoint led again and 
again to the discovery that the antecedent of motion is some other 
motion, and one after another of the so-called “forces” were thus 
resolved into motions, until at last only gravity and affinity, and 
perhaps magnetism, remain as unexplained antecedents of motion. 
But gravity, affinity, and magnetism are included under one term, 
“ attraction,” by those who hold that there is yet a force—something 
other than motion which produces motion. Attraction, then, is left. 
Sometimes these same philosophers speak of “ attraction and repul- 
sion.” If, then, all forces the actions of which are thoroughly 
known are resolved into antecedent motions, it is indeed an induc- 
tive hypothesis worthy of consideration that the antecedents of the 
phenomena of attraction and repulsion may also be regarded as 
modes of motion. 
But this hypothesis is reached by another method. It is known 
that motions may be transmuted from one kind or mode into an- 
other.. Affinity can be transmuted into motion, and motion into 
affinity. If we wish to obtain the mode of motion called electricity, 
we may derive it from mechanical motion through friction, or we 
may derive it through affinity in the voltaic cell. If we combine a 
gramme of hydrogen with oxygen, 34,000 units of heat—a mode of 
motion—are developed. If a gramme of hydrogen be combined 
with iodine, 3,600 units of heat—a mode of motion—are absorbed. 
But why introduce single illustrations? A large part of all the 
powers used by man in the industries of the world are derived from 
affinity. Affinity, therefore, is the equivalent of motion. By a 
similar process it is shown that gravity can be transmuted into mo- 
tion and motion into gravity, and the trasmutation of magnetism 
into motion and of motion into magnetism is well known. 
It is thus seen that while motion may be derived from the so- 
called forces, gravity, affinity, and magnetism, these so-called force 
