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Rh with radio-active bodies, and frequently alluded to electrons as "chipped atoms."

The forces of the material universe, such as cohesion, adhesion, heat, electricity, magnetism, etc., engaged the attention of Kelvin. Though the amount of energy in the universe is constant, it is always being degraded from higher to lower forms. This is Kelvin's law of the "dissipation of energy," which means that the universe is not a clock wound up to go for ever. Energy is every moment running down, and sometime in the measureless past must have been started, and sometime in the unbounded future it must be wound up again, or stop for ever.

Kelvin's theory of vortex motions, as applied to atoms and molecules, is of vast importance. It is a type of motion in a frictionless, incompressible, primordial fluid which might account for the known properties of matter.

Many of Kelvin's papers are only understood by expert mathematicians. There is hardly a department in physics which he did not make his own: molecular physics, electricity, dynamics, the theory of gases, heat, thermo-dynamics, the theory of energy, etc.

Kelvin was also a great inventor, and his appliances are manufactured by Messrs James White of Glasgow, who employ nearly two hundred skilled workmen and electricians.