Various theories have been propounded as to the cause of the Gulf Stream; but Lieut. Maury was the first man who had accumulated together sufficient evidence to place the subject on a philosophical basis. We must come to the principles of Nature, in order to explain the combination of causes which lead to this great result. In the first place, the sea is salt; geology establishes the fact that it has been so from the beginning. If it was not salt, none of these effects would be produced; so that the saltness of the ocean is the key stone of the arch which will carry us over the difficulty. The winds have little or nothing to do with the currents; they are in the mightiest whirlwinds and storms but as little puffs upon the surface, and leave the deep sea currents calm beneath them. Then we know that water is a non-conductor of heat; that though it is capable of receiving the greatest amount of heat, it does not conduct it. This explains one great phenomenonthat the stream of hot water runs through the cold without mixing with it. There is the same indisposition to amalgamate between salt-water and fresh-water. In fact, water seems a very unsocial element, and won't mix with the same element under other conditions till it is forced. Another fact is, that water in motion will not mix with water at rest: so here we have those wonderful principles which illustrate the great river running through the ocean. The Gulf Stream never touches the earth at the bottom of the ocean. Why? if it did the heat would escape, as the earth is a conductor of heat. But there is below the stream a cushion of cold water, so that it runs through an entire channel of cold water, that it may conduct its heat 3000 miles across the ocean. Again, cold water is heavier than hot water, and salt water heavier than fresh water. All the currents of the ocean, in every part of the world, are occasioned by this one thing-the inequality in the weight of water. Three great

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causes produce this inequality in the weight of water-evaporation, precipitation, and, what is very curious, the third cause is the work of the little shelly creatures at the bottom of the ocean. The evaporation in part of the Atlantic Ocean would produce 15 feet of solid water in a year; and if it could be accumulated, it would cover three millions of square miles. Of course, if this was done all at once, it would destroy the world. If all the salt in the sea were precipitated, or made solid, it would cover more than half the continent of America a mile deep. There is nearly half an ounce of solid matter in every pound of sea water. If this matter were allowed to accumulate it would destroy the natural equilibrium. But GoD called the insects in; and the thousands of coral reefs in the Pacific Ocean are constantly in process of formation by these little creatures. Every shell-fish we picked up on the sea shore, took a portion of this matter upon its back, thus the accumulation of lime, soda, iron, &c., is prevented: the heat goes up in evaporation, and comes back to us in refreshing showers. So that we are indebted for our climate, to the wonderful labours of the millions of little creatures on the other side of the globe. They have power to put the whole sea in motion, from the equator to the poles.

Let us now turn our attention for a short time to the currents of the ocean. It is a remarkable fact, that (with the exception of Behring's Straits) whereever there is a surface current running one way, there is always an under current running in an opposite direction, perhaps two miles deep. Thus you see the currents of the ocean, like the circu lation of the blood, if they all ran one way would cause disorganisation. But perhaps you are ready to say,-How do you know this? How can you tell there is an under current running five miles an hour? The method by which this is discovered, is a very ingenious and simple one. 1 will endeavour to

explain it to you. They take a large piece of wood, and weight it sufficiently to sink it as far as they please. They then attach a small barrel or float to it, with a line; and then a most beautiful phenomenon is the result, which greatly astonishes the sailors. The barrel or float sets off against wind or surface tide, as if it were drawn by some monster. shall be very much surprised if "Jack" doesn't make some more practical use of this fact, and sink something large enough to drag his ship along. It is upon the same principle, that while the great body of surface water comes down the Davis Strait, and with such power as to force the Gulf Stream into a horse shoe bend, an under current of great depth and force is running into that ocean.

The "Resolution," which as you may remember, was one of the vessels that went in search of Sir John Franklin, was blocked up with ice, and abandoned by the crew in these Straits. It was found afterwards by an American vessel in the Atlantic, having been brought down upon a huge iceberg, by the force of the surface current.

One large and single iceflaw brought down these Straits, was 300,000 square miles in extent, upwards of 7 feet thick, and eighteen thousand millions of tons weight.

The Strait of Gibraltar, which is very deep, passes into the Mediterranean Sea. Our forefathers, hundreds of years ago, knew the fact that the Atlantic is always rushing in at a great pace through this strait, and although there is no outlet, the Mediterranean is not enlarged, nor is the water any more salt than the ocean outside. How is this? There must be some secret way out for these waters, or the Mediterranean Sea would become like the Dead Sea, a mass of salt, and dry up. Where is the escape, then? The fact is, though there are those who deny it to this day-that there is a peaceful under current running out, as the top one runs in.

In the year 1724, a naval action took place between a French frigate and a Dutch merchantman: the French, however, had it all their own way; for as soon as the Dutchman showed fight, they poured a broadside into him and sunk him, though they saved the crew. In a few days afterwards, the sunken vessel came up again, just as a dead body comes up after having lain a certain time in the water, at the distance of 240 miles to the westward of where she went down, right in the very teeth of the current running into the Mediterranean Sea,-proving the fact of an under current.

I must now say a few words respecting Inland Lakes. The Caspian Sea, the Great Salt Lake in America, where the Mormons are, with others that we know of, are lakes of salt water not connected with the sea. It is a curious fact, that wherever there is an inland lake into which rivers run, but out of which no rivers flow into the sea, that lake must be salt water. I confess it seems hard to believe, but such is the case.

And it is also found that the water in these lakes is of the same density as the water in the ocean. And if there were not other processes going on, such lakes would become a mass of salt; but there are other processes going on, and these great principles are equipoised.

The waters of the Caspian Sea are the same height now as they were thousands of years ago, so that the supply and demand are nicely balanced.

I have now briefly to introduce to you another subject;-I cannot say distinct from it, but connected with it in the marvellous. I have taken you into many of the oceans, I am now going to take you into the air,-that subtle, invisible, wondrous fluid, in which we live, and move, and have our being, and which is now pressing upon you and me at this moment with a weight of many tons. At times it is so calm and tranquil that the little lily of the

field is not moved by it; at other times it is one of the most powerful engines that Almighty God is pleased to put in motion. I must go on through the atmosphere, this breathing place which is supposed by some to be 50, and by others 500 miles high. You see they have got a deep sea-line to measure the ocean, but they have got nothing on which to go up and measure the air.

There are three atmospheric phenomena, called cloud rings, which encircle the earth, but not uninterruptedly; there are breaks in them over some portions of the land, but none over the sea.

These are the conductors of the winds, the lungs of the universe. The equatorial cloud belt varies from 60 to 400 miles, sometimes being above and sometimes below the equinoctial line. This is the region of perpetual clouds and perpetual calms, also of incessant rains.

Travelling North and South at different periods of the year, these rings occasion the rainy seasons in North and South America; in some parts of the world, as you are no doubt aware, they have their

rain at one season.

Some of you may be inclined to ask what the cloud rings have to do with the wind? they have everything to do with it. Hitherto the winds and waves have been looked upon as symbols of uncertainty; as fickle as the winds and waves is a common expression; but as science has progressed, we have discovered their motion. And though we can never be said to hold the winds in our fists, yet are they subject to regular and fixed laws, as certain as the planets in our system, or the stars in the firmament. The trade winds are always found in a certain portion of the globe,and always move in one regular course. The north-east winds blow always from the north to the equator, and the south-east trade winds the up to the equator. Day after day, year after year are these winds continuously blowing, so that