ism, and to be either the immediate agency of the Deity, or affected by a law originally established and impressed on all matter by him. That the projectile force was at first given by the Deity, is evident; Since matter can never put itself in motion, and all bodies may be moved in any direction whatever, and yet the planets, both primary and secondary, move from west to cast, in lines nearly coincident, while the Comets move in all directions, and in planes very different from each other; these motions can be owing to no mechanical cause or necessity, but to the free will and power of an intelligent Being.

Whatever Gravity be, it is plain that it acts every moment of time; for if its action should cease, the projectile force would instantly carry off the planets in straight lines from those parts of their orbits where Gravity left them. But the planets being once put in motion, there is no occasion for any new projectile force, unless they meet with some resistance in their orbits, nor for any mending hand, unless they disturb each other too much by their mutual attraction.

It is found that there are disturbances among the planets in their motions, arising from their mutual attractions, when they are in the same quarter of the Heavens, and the best modern observers find that our years are not always precisely of the same length.

If the planets did not mutually attract each other, the areas described by them would be exactly proportional to the times of description. But observations prove that these areas are not in such exact propor

ens.

tions, and are most varied when the greatest number of planets are in any particular quarter of the HeavWhen any two planets are in conjunction, their mutual attractions which tend to bring them nearer to each other, draws the inferior one a little nearer to him; by these means, the figure of their orbits is somewhat altered, but this alteration is too small to be discovered in several ages. By the most simple law, the diminuation of Gravity, as the square of the distance increases; the planets are not only retained in their orbits, when whirling with such immense velocity around their central Sun; but an eternal stability is insured to the solar system. The small derangements which affect the motions of the Heavenly bodies, are only apparent to the eye of the Astronomer, and even these after reaching a certain limit, gradually diminish, till the system regaining its balance, returns to that state of harmony, and order which has preceded the commencement of these secular irregularities. Even amidst the changes and irregularities of the system, the general harmony is always apparent; and those partial and temporary derangements, which vulgar minds may seem to indicate a progressive decay, serve only to evince the stability and permanency of the whole.

In contemplation of such a scene, every unperverted mind must be struck with that astonishing wisdom which framed the various parts of the Universe, and bound them together by one simple, yet infallible law. In no part of creation, from the smallest insect to the highest seraph, has the Supreme Architect of the Uni

verse left himself without a witness; but it is surely in the Heavens above, that the Divine attributes are most gloriously displayed.

Interrogations. for Section Fifth.

From what source do the circular motions of the planets arise ?

With what velocity would projected bodies continue to move if they met with no resistance?

What is meant by the centrifugal force?
What is meant by centripetal force?

Are the centripetal and centrifugal forces ever equal while the planet performs its revolution round the Sun ?

When the power of Gravity exceeds the projectile force, why does it not draw the planets to the Sun ?

When the projectile, or centrifugal force exceeds the attraction, why does it not fly off, and never return? When these forces are equal, why do they not move in perfect circles?

What will a double projectile force balance ?

In what case could the projectile be made to balance the gravitating power in such manner that the planets should move in a perfect circle ?

If the centrifugal forces should at once be destroyed, in what time would each of the planets fall to the Sun ? In what time would the Moon fall to the earth?

What rule for finding the time in which would they fall to the Sun?

What do the rapid motions of the Moons of Jupiter and Saturn demonstrate?

Do the Sun and planets continually attract each other ?

Should gravity instantaneously cease, what would be the consequence ?

Are the motions of the planets continually the same? Do they continue to move exactly in the same path at every revolution?

By what simple law does gravity diminish?

SECTION SIXTH.

ON LIGHT AND AIR.

LIGHT consists of exceedingly small particles of matter, issuing from a luminous body, as from a lighted candle. Such particles of matter constantly flow in every direction. By Dr. Neiwentyt's computation, 148,660,000,000,000,000,000,000,000,000,000,000,000, 000,000 particles of light in one second of time flows from a candle, which number contains at least 6,337,245,000,000 times the number of grains of sand in the whole earth; supposing 100 grains of sand to be equal in length to an inch, and consequently every cubic inch of the earth to contain one million of such grains. These amazingly small particles, by striking upon our eyes, excite in our minds the idea of light, and if they were as large as the smallest particle of matter discernible by our best microscopes, instead of being serviceable to us, they would soon deprive us of sight by the