RENDERING

, in Building. See Pargeting.

REPELLING Power, in Physics, is a certain power or faculty, residing in the minute particles of natural bodies, by which, under certain circumstances, they mutually fly from each other. This is the reverse or opposite of the attractive power. Newton shews, from observation, that such a force does really exist; and he argues, that as in algebra, where positive quantities cease, there negative ones begin; so in physics, where the attractive force ceases, there a Repelling force must begin.

As the Repelling power seems to arise from the same principle as the attractive, only exercised under different circumstances, it is governed by the same laws. Now the attractive power we find is stronger in small bodies, than in great ones, in proportion to the masses; therefore the Repelling is so too. But the rays of light are the most minute bodies we know of; and therefore their Repelling force must be the greatest. It is computed by Newton, that the attractive force of the rays of light is above 1000000000000000, or one thousand million of millions of times stronger than the force of gravity on the surface of the earth: hence arises that inconceivable velocity with which light must move to reach from the sun to the earth in little more than 7 minutes of time. For the rays emitted from the body of the sun, by the vibrating motion of its parts, are no sooner got without the sphere of attraction of the sun, than they come within the action of the Repelling power.

The elasticity or springiness of bodies, or that property by which, after having their figure altered by an external force, they return to their former shape again, follows from the Repelling power. See REPULSION.

REPERCUSSION. See Reflection.