those parts where the pressure is greatest, namely, in those where the moon is near the horizon. The sca, which otherwise would be spherical, upon the pressure of the moon must form itself into a spheroidal or oval figure, whose longest diameter is where the moon is vertical, and shortest where she is in the horizon; and the moon shifting her position as she turns round our globe once a day, this oval of water shifts with her, occasioning thereby the two floods and ebbs observable in each five and twenty hours. The spring-tides upon the new and full moons, and the neap tides upon the quarters, are occasioned by the attractive force of the sun in the new and full, conspiring with the attraction of the moon, and producing a tide by their united forces. Whereas in the quarters the sun raises the water where the moon depresses, and on the contrary; so as the tides are made only by the difference of their attraction. The sun and moon being either conjoined or opposite in the equinoctial, produce the greatest spring-tides. The subsequent neap-tides being produced by the tropical moon in the quarters, are always the least tides.

But then from the shoalness of the water in many places, and from the narrowness of the straits, by which the tides are in many places propagated, there arises a mighty diversity, which, without the knowledge of the places, cannot be accounted for.

Dr. Cheyne has taught me to take notice of one thing more. If our earth had any more than one moon attending it, we should receive probably a detriment from it, rather than an advantage. For at the conjunction and opposition with one anoth

er, and with the sun, we should have tides that would raise the waters to the tops of our mountains, and in their quadratures we should have no tides at all.

O my soul, beholding the moon above, look up to God, who hath so wisely proportioned her, for the designs on which He placed her there.

The sea is the grand fountain of those fresh waters, which supply and enrich the earth, and by convenient channels are carried back to the place from whence they came; how equally are these fresh waters distributed ? how few Antigua's in the world? how agreeably are they disposed? and what a prodigious run have many of the rivers? The Danube, in a sober account, as Bohun computes, runs fifteen hundred miles in a straight line from its rise to its fall. The Nile, according to Varenius, allowing for curvatures, runs three thousand miles; and the Niger two thousand four hundred; the Ganges twelve hundred; the Amazonian above thirteen hundred Spanish leagues.

"But is it not high time for us to hear the voice of many waters!

"One celebrating the bounty of our God to us in the water, so expresses it: The contemplation may be carried to the element that is next above it."

Long since have we been taught such notes as these, "O Lord, how manifold are thy works! in wisdom hast thou made them all. The earth is full of thy riches. And so is the great and wide sea, wherein are swimming things innumerable.

"But can we look on the sea, and not see a picture of a troublesome world; see and be instructed."

APPENDIX.

WE can scarce leave the water without some remarks on our fluids; and we will be more particularly indebted to Dr. Cheyne for hinting them. How frugal is nature in principles, and yet how fruitful in compositions and in consequences! The primary fluids are but four, water, air, mercury and light. It is but seldom that three of these are much compounded with others. It is water alone, it is lymph, that is mostly the basis of all other mixtures; and it is the parts of solid bodies floating in this fluid that produce all our pleasant and useful varieties of liquors.

How vast the difference between the specific gravities of our fluids! Mercury is about eight thousand times heavier than air. Air must have choaked us, if it had been half so heavy as mercury.

And yet mankind in its present circumstances of the blood vessels, under frequent obstructions, could not well have done without such an heavy fluid as mercury.

All fluids agree in the condition of the direction of their pressure upon the sides of the containing vessel. This pressure is for ever communicated in lines perpendicular to the sides of the containing vessel. This beautiful and uniform property of all fluids necessarily follows from the sphericity of their constituent particles.

Our doctor's conclusion is as I would have it. "Now could any thing but the almighty power of God have rounded those infinite numbers of small particles whereof fluids consist? Or could any thing but his wisdom have assigned them their true dimensions, their exact weights, and required solidities?"

it, Behold, there is a God, whom I ought for ever to love, serve, and glorify. Yea, and if I am tempted to the doing of any wicked thing, I may reflect that it cannot be done without some action wherein the weight of matter operates. But then I may carry on the reflection, How near am I to that glorious God, whose commands I am going to violate! Matter keeps his laws; but, O my soul, wilt thou break them? How shall I do this wickedness, and therein deny the God, who not only is above, but also is most sensibly now exerting his power in the very matter, upon which I make my criminal misapplications!"

Before we go any further, it appears high time to introduce an assertion or two of that excellent philosopher Dr. Cheyne, in his philosophical principles of natural religion. He asserts, and with demonstration, (for truly without this he asserts nothing!) that there is no such thing as an universal soul, animating the vast system of the world, according to Plato; nor any substantial forms, according to Aristotle; or any omniscient radical heat, according to Hippocrates; nor any plastic virtue, according to Scaliger; nor any hylarchic principle, according to More. These are mere allegor ical terms, coined on purpose to conceal the ignorance of the authors, and keep up their credit with the credulous part of mankind. These unintelligible beings are derogatory from the wisdom and power of the great God, who can easily govern the machine he could create, by more direct methods than employing such subservient divinities; and indeed these beings will not serve the design for which we invent them, unless we endow them with faculties above the dignity of secondary agents. It is now plain from the most evident

principles, that the great God not only has the springs of this immense machine, and ail the several parts of it, in his own hand, and is the first mover; but that without his continual influence the whole movement would soon fall to pieces. Yet besides this, he has reserved to himself the power of dispensing with these laws whenever he pleases.

My doctor has made it evident, that it is not essential to matter to be either in rest or in motion; but though there is in matter a vis inertiæ, by which all bodies resist, to the utmost of their power, any change of their state, whether of rest or motion; yet this vis is not essential to matter, but a positive faculty implanted therein by the Author of nature. It is therefore evident that the preservation of a body in rest or in motion, after the first instant, absolutely depends on the almighty God, as the cause. No part of matter can move itself, nor when put into motion, is this motion absolutely essential to its being, nor does depend upon itself; and therefore the preservation of this motion must have its dependence on some other cause. But there is no other cause assignable besides the omnipotent cause, who preserves the being and faculties of all natural agents.

Great God, on the behalf of all thy creatures, I acknowledge in thee we move and have our being!

ESSAY XXII. Of the WATER.

PURE water is a fluid void of all sapor, and seems to consist of small, smooth, round and porous particles, that are of equal diameters and equal gravities. There are also between them spaces, that are so large, and ranged in such a manner, as