Original terms of Day and Night -- Motion the effect of a Divine power -- Commencement of Time -- Utility of Day and Night -- Religious improvement of Time -- Sin moral darkness -- The Gospel a Light to dispel it -- A Christian the subject of a transition from the one state to the other. The separation of _light_ from the _darkness_, was the work of the _first day_. This was an arrangement made by infinite Wisdom, as well as a display of almighty power. When this took place, it is highly probable that God gave to the earth its rotation upon its own axis, to produce the necessary succession of _day_ and _night_. “The word ערב _éreb_, which we translate _evening_, comes from the root ערב _ârab_, to _mingle_, and properly signifies that state in which neither absolute darkness, nor full light, prevails. It has nearly the same grammatical signification with our _twilight_, the time that elapses from the setting of the sun till he is eighteen degrees below the horizon, and eighteen degrees before he arises. Thus we have the morning and evening twilight, or _mixture_ of light and darkness, in which neither prevails; because, while the sun is within eighteen degrees of the horizon, either after his setting, or before his rising, the atmosphere has power to refract the rays of light, and send them back to the earth. The Hebrews extended the meaning of this term to the whole duration of night, because it was ever a _mingled_ state; the moon, the planets, or the stars, tempering the darkness with some rays of light. From the _ereb_ of Moses came the Ερεβος _Erebus_ of Hesiod, Aristophanes, and other heathens, which they _deified_, and made with _nox_, or night, the parent of all things. The word בקר _boquer_, which we translate _morning_, from בקר _boquar_, he _looked out_, is a beautiful figure, which represents the morning as _looking out_ at the east, and illuminating the whole of the upper hemisphere.”[47] All bodies continue in a state of rest, till they are put into motion by some external force impressed on them. Motion is the removal of a body from one place to another, or a continual change of place.[48] Any force acting on a body to move it, is called a _power_. The _momentum_, or quantity of motion, is in proportion to the force impressed. The heavier any body is, the greater is the power required to move it. There are but three possible ways of accounting for motion:--either by supposing that there has been an infinite succession of impulses communicated from one body to another from eternity, without any active principle either in matter or without it: or, that there is an active principle in matter that renders it self-active, and motion essential to it: or, else, that there is a Being distinct from matter, and is the cause of its motion.