from the British government expressive of the high interest felt by his department in the proposition, and authorizing the Superintendent of the Naval Observatory to confer as to such a uniform plan of observations, with the proper officers, at home and abroad, and in concert with them to agree upon a system of observations both on sea and land. Mr. Maury proceeded to publish a pamphlet embodying the features of his plan, to which he gave a wide circulation. Several governments responded to the proposition, as did many learned societies. When the original proposition, as amended by the American government, to include the sea also in the system of research, went back to the British government, it was by that government referred to the President and Council of the Royal Society for a report. It was most favorably entertained by that illustrious body, and the labors of Lieut. Maury are represented to the government in the most flattering terms. The efforts already made in this country up to that time, (1852,) are thus comprehensively exhibited in that Report:

"The proposition and the results obtained, of Lieut. Maury, to give a greater extension and more systematic direction to the meteorological observations to be made at sea, appear to be deserving of the most serious attention of the Board of Admiralty. In order to understand the importance of this proposition, it will be proper to refer to the system of observations which has been adopted of late years in the Navy and Merchant Service of the United States, and to some few of the results to which it has actually led. Instructions are given to naval captains and masters of ships, to note in their logs the points of compass from which the wind blows, at least once in every eight hours; to record the temperature of the air, and of the water, at the surface, and when practicable, at considerable depths of the sea; to notice all remarkable phenomena which may serve to characterize particular regions of the ocean, more especially the direction, the velocity, the depth, and the limits of the currents. Special instructions also are given to whalers to note down the regions where whales are found, and the limits of the range of their different species. Detailed instructions are given to all American ship-masters upon their clearing from the custom house, accompanied by a request that they would transmit to the proper office, after their return from their voyage, copies of their logs, as far at least as they relate to their observations, with a view to their being examined, discussed, and embodied in Charts of the Winds and Currents, and in the compilation of Sailing Directions to every part of the globe. For some years the instructions furnished received very little attention, and very few observations were made or communicated; the publication, however, in 1848, of some charts founded upon the scanty materials which had come to hand, or which could be collected from other sources, and which indicated much shorter routes than had hitherto been followed to Rio, and other parts of South America, was sufficient to satisfy some of the more intelligent ship-masters of the object and real importance of the scheme; and in less than two years from that time, it had received the cordial cooperation of the master of nearly every ship that sailed. Short as is the time that this system has been in operation, the results to which it has led have proved of very great importance to the interests of navigation and commerce. The routes to many of the most frequented ports in different parts of the globe, have been materially shortened; that to San Francisco, in California, nearly one-third; a system of southwesterly monsoons,

in the equatorial regions of the Atlantic, and on the west coast of America, has been discovered; a vibratory motion of the trade wind zones, with their belts and calms, and their limits for every month of the year, has been determined; the course, bifurcations, limits, and other phenomena of the Gulf Stream have been more accurately defined; and the existence of almost equally remarkable systems of currents in the Indian Ocean, on the coast of China, on the northwestern coast of America, and elsewhere, has been ascertained. There are in fact very few departments of the science of meteorology and hydrography, which have not received very valuable additions; whilst the most accurate determination of the parts of the Pacific Ocean (which are very limited in extent) where the sperm whale is found, as well as the limits of the range of those of other species, has contributed very materially to the success of the American whale fishery, one of the most extensive and productive of all the fields of enterprise and industry."

It was ascertained that a number of the leading governments of Europe were averse to making any change in their established systems of meteorological observations on the land, while they would heartily coöperate in promoting a uniform system on the sea. It was therefore deemed advisable to confine the proposed concert to observations at sea, and, at the suggestion of Lieut. Maury, official invitations were issued by Hon. Mr. Everett, then Secretary of State, to a conference to be held at Brussels, in August, 1853. The conference met accordingly, and consisted of representatives from Portugal, France, England, Belgium, Denmark, Sweden, Norway, Russia, Holland, and the United States. By order of the Secretary of the Navy, Lieut. Maury was commissioned to attend the conference on the part of our government. The history of this celebrated and important meeting is given in the work before us, in full, and indeed with needless prolixity, a fault which characterizes a large portion of the documents that proceed from Washington.

The "abstract log," or formula for observations agreed on by the conference, consisted of twenty-two blank columns, with an additional column of "Remarks." It might be tedious to enumerate the various particulars which constitute the headings, but it may be truly said they leave little to be desired, embracing as they do every subject relating to the phenomena of the ocean and the atmosphere that can contribute to our knowledge of either.

Under a system of observations so excellent in itself, and rendered efficient by so many zealous collaborators, we may reasonably anticipate that our knowledge of the ocean will be rapidly extended; that new laws governing its winds and its currents will be successively developed, until it will appear that every wave that rolls, and every breeze that blows is a part of some great system; that from the knowledge thus acquired will arise new facilities for navigation, and be opened new mines of

wealth; that as in other departments of nature, man having now become the master where he was before the slave, he will no longer be borne off his track by the currents, or wrecked by the winds and waves, but will turn to his own account the violence of these elements, and their seeming irregularities, and compel them to speed him on the way. With such visions of the future, we may now advantageously take a comprehensive view of the ocean, in its phenomena, its laws, and its useful products.

The waters of the ocean cover nearly three-fourths (or more exactly, five sevenths) of the surface of the globe; and of the thirty-eight millions of miles of dry land in existence, twentyeight belong to the northern hemisphere. The mean depth of the ocean has been variously stated, but may for the present be taken at four miles: the numerous soundings now in progress will soon enable us to speak with more definiteness on this point. Enough has already been done to prove that the depth is exceedingly unequal; that like the surface of the earth, the bottom of the ocean here rises in mountain peaks, and there sinks in deep valleys. Until recently the deepest sounding ever made, was that by Captain Scoresby in the polar seas, which was short of a mile and a half. As late as 1848, the maximum sounding was that of Captain Ross, in the South Atlantic, and gave 27,600 feet, or a little over five miles, without finding bottom. But more recently, at a point of the Atlantic farther north, Lieut. Walsh, of the U. S. Schooner Taney, sounded, without reaching bottom, to the depth of 34,200 feet, or nearly 6 miles. Within a short time Captain Denham communicated to the Royal Society a report of having reached the bottom of the Atlantic, in a passage from Rio Janeiro to the Cape of Good Hope, at the astonishing depth of 7,706 fathoms, or 8 miles; a depth so profound, that the plummet occupied in its descent from the reel nearly 9 hours. From these results it appears that the depths of the ocean exceed the heights of the mountains, since the loftiest summits of the Himmalaya are little more than 28,000 feet, or 5 miles. Notwithstanding these enormous depths, there are large tracts of the ocean comparatively shallow; and in the immediate vicinity of places where no bottom could be found, were spots of no uncommon depths. These facts indicate that the bed of the sea is diversified like the surface of the earth. The Gulf of Mexico is thought not to exceed on an average one mile; and the Greenland seas are of such moderate depth, that whales, when harpooned, often run to the bottom, as is indicated by their appearance when they rise again to the surface. Whales are even supposed to seek a part of their food at the bottom of the sea.

The pressure that bodies must undergo at such vast depths, is enormous. As the pressure of a column of water varies in proportion to the depth, and is found by experiment to amount to 500 pounds on a square foot, at the depth of 8 feet, it would be, at one mile below the surface, on the same area, 330,000 pounds; and at the depth of 83 miles (the deepest sounding yet made) it would exceed 1200 tons to the square foot. It has long been known that square bottles let down to even a moderate depth into the sea, are crushed; and that junk bottles, when sunk to a greater depth, come up filled with water, if previously empty, or if before full of fresh water, this is displaced and the bottle, when drawn up, is found full of salt water, the great compression of the cork having permitted the exchange. The late Mr. Jacob Perkins, many years ago, instituted an interesting series of experiments of this kind, during his voyage across the Atlantic, with the view of ascertaining the compressibility of water; and afterwards, in Philadelphia, he applied by means of the hydraulic press, a force no less than nearly 2000 tons to the square foot, without changing the water from the fluid to the solid state, as some have imagined might be the case with water under the pressure sustained by sea water in the lowest depths of the ocean. Water itself, however, by such an incumbent pressure, would be sensibly reduced in bulk, and its density would be proportionally increased; so that substances which, like the human body, but little exceed water in specific gravity, might float at a certain depth, before reaching the bottom, if they did not by the same cause themselves undergo a still greater compression. This is commonly the case with light bodies submerged to a great depth, so that parts of a vessel when wrecked in deep water, which would float near the surface, never rise. The Greenland whale is said sometimes to descend to the depth of a mile, but always to come up exhausted and blowing out blood.

Specimens of the matter that was brought up from the bottom of the sea, by our vessels employed in taking deep soundings, at the depth of more than two miles, were transmitted to Prof. Bailey, of West Point, (well known for his great skill in microscopic examinations,) and were found to be filled with the remains of exceedingly minute animalcules, consisting of calcareous shells. Prof. Bailey thinks it impossible that these microscopic animals lived at the depths where those shells are found, but that their home is near the surface, and that when they die their shells settle to the bottom. Mr. Maury remarks that we are taught thus to view the surface of the sea as a nursery teeming with nascent organisms; its depths as the

cemetery for families of living creatures, that outnumber the sands of the sea-shore for multitude.

The temperature of the ocean undergoes but slight variations in the torrid zone, being generally from 80° to 83°, and in the higher latitudes the variations are much less than on the land. It becomes, therefore, a fountain of cool breezes in summer and of warm gales in winter. In certain parts of the Indian Ocean, the hottest sea in the world, the water reaches the heat of 90°. At a certain depth below the surface throughout the ocean, we come to a cold stratum of invariable temperature, that of 40°. At the equator this is found at the depth of a mile and a quarter, (7,200 feet,) but it comes continually nearer and nearer to the surface until, in latitude 56°, it reaches quite to the surface. North of this the cold water is uppermost, and in latitude 70° the depth of the invariable stratum is three-fourths of a mile, (4,500 feet.) Nothing could be more favorably situated for evaporation than the waters of the ocean, whether we regard the extent of surface, the elevated temperature, or the agitation by winds; and, accordingly, the amount of water thus raised into the atmosphere, is prodigious, being estimated as sufficient, were none returned to it, to sink the level of the ocean four feet per annum, implying more than 3,000,000 of tons weight, to every square mile. One portion of this vapor is precipitated upon the ocean again; another portion is borne by the winds over the lands, and waters the earth with showers, feeds the springs, sustains vegetable and animal life, and then returns again to the ocean by the rivers. These restore to the sea what the land had before borrowed from it; and thus, by this constant exchange, the land is not drained and the sea is not full. The Mississippi alone delivers to the Gulf of Mexico, nearly fifteen trillions of cubic feet, or about 110 cubic miles of water, which the valley of the Mississippi alone had borrowed from the ocean. These statements give us some faint idea of the energy which Nature puts forth in watering the earth. Her beneficent care is still further manifested in the purifying processes which water undergoes in this circulatory system, which is carried on between the sea and the land. All the impurities that can soil the person, or clothing, or dwelling of man; all that can corrupt the air from the decay of organic substances, is received by the rivers and borne away to the sea. Here the tides and the waves meet it, and sweep it far from the shore, and deposit it in the ocean depths. In return, a constant supply of pure water is raised from the sea by distillation, leaving behind all saline and all other foreign ingredients of sea-water; it is borne over the land by winds, where it either falls in