149 
STUDIES OF MATTER AND LIFE. 
By HENRY J. SLACK, F.G.S.,’ Sec. R.M.S. 
T HE discoveries of recent science have greatly affected the 
notions we are able to form concerning the relations of force 
and matter, and likewise of the connection between physical 
agencies and manifestations of life. In studies of this descrip- 
tion we are struck with the amount of force that lies potentially 
in extremely minute quantities of matter ready for vigorous 
action the moment the right stimulus is applied, and by the 
way in which quickness of motion makes up for smallness 
of weight. The physical inquirer is not obliged to tarry for the 
curious and important investigations of the metaphysician; 
he need not attempt to settle the fundamental questions — what 
is matter ? and what is force ? — in the ultimate constitution of 
either. To the experimentalist, matter is known by what it 
does ; and whether the problem before him relate to mechanics, 
chemistry, electricity, light, heat, or gravitation, it is with 
matter in motion and exhibiting force, because in motion, 
that he has to deal. The same may be said of all the physical 
processes and manifestations of life, though we seem no nearer 
than the ancient Greeks were when we try to understand the 
connection between motions of particles and the phenomena of 
feeling and thought. 
Light, heat, electricity in its various forms, chemical force 
and nerve force, are not only now classified as “modes of 
motion,” but the motion in each manifestation of these forces 
appears to be wave motion ; and it is probable that gravitation, 
the correlation of which with other forces is not yet estab- 
lished, may at last be found to be a wave motion also. In wave 
motion each particle moves, pendulum-wise, backwards and 
forwards in a small curve, transmitting the motion to the par- 
ticles before it in more or less rapid succession, the motion 
becoming weaker as the original impulse is divided amongst 
more and more particles, until at last it is so enfeebled that it 
cannot be observed. The common illustration of throwing a 
