persistence of speeds; the evolutionary theory the persistence of existence.
There are systems of stars, and every system is a body. The one to which our earth belongs is well known, for the solar system is the theme of the venerable science of astronomy. The earth itself is composed of four grand bodies: an outer envelope of air or atmosphere, a middle envelope of water or hydrosphere, an inner envelope of rock or lithosphere, and the grand central nucleus or centrosphere. Neglecting the two outer envelopes and considering only the stony crust, we find that it is composed of many bodies or formations and these of rocks, while there are many plants and animals, and all again are divided into grains, crystals or cells, and the grains, crystals or cells are divided into molecules, and molecules are composed of other molecules, until at last chemical atoms are reached; so it is discovered that the universe is a hierarchy of bodies.
The universe is a hierarchy of bodies composed of bodies and these again composed of bodies in a vast succession as they are reduced by analysis. When we come to discuss the relations of these bodies to one another it will be convenient and conduce to exact expression if we make a distinction between bodies and particles, and speak of a body when we wish to consider it as a unit and then speak of its particles when we wish to speak of the parts of which it is composed. A body, therefore, is a body of particles which are many in one, the one being a body; the many particles severally may be bodies composed of particles, that is, one composed of many. The solar system is a body of particles, the
