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Hawaii. The light rose and spread like morning upon the mountains, and its glare was seen on the opposite side of the island. It was distinctly visible for more than one hundred miles at sea, and at the distance of forty miles fine print could be read at midnight. . . .

"From the period, thirty-six hours, which the lava required to reach the sea, an average velocity of four hundred feet an hour is readily deduced, as stated by Captain Wilkes. Yet as the lavas issued from various fissures along the course, the result cannot be correctly compared to an overflow of fluid; it is rather the rate of progress of the eruption than of the motion of a flowing liquid.

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"The thickness of the stream of lava was estimated by Dr. Pickering as averaging ten or twelve feet. In some places it was not over six feet. The whole area, judging from the surveys, covers about fifteen square statute miles and reduced to feet, and multiplying by the depth, 12 feet, gives, for the amount of ejected lava, 5,018,000,000 cubic feet; to which, if we add for the previous ejections of the same eruption, three more square miles, it gives 6,023,000,000 of cubic feet for the whole amount of lavas which reached the surface.*

"We have a still more accurate means of estimating the amount of lavas which passed from Kilauea, in the actual

* This calculation, however, if we understand it, respects only the mass of the lava that remains on the surface between Kilauea and the shore. It takes no notice of the vast cataract that plunged into the ocean during the three weeks of the eruption. If that were taken into the account, the whole sum that was ejected would be seen to be immensely greater than this estimate.

cubic contents of the emptied pit. The area of the lower pit, as determined by the surveys of the Expedition, is equal to 38,500,000 square feet. Multiply this by 400 feet, the depth of the pit after the eruption, we have 15,400,000,000 cubic feet for the solid contents of the space occupied by lavas before the eruption, and, therefore, the actual amount of the material which flowed from Kilauea. This is two and a half times the amount obtained from the estimated extent of the eruptions. The difference may be accounted for partly on the ground that fissures were filled as well as surfaces overflowed, and also that there may have been eruptions beneath the sea not estimated.* This amount is equivalent to a triangular ridge eight hundred feet high,

* Here there is an omission also from the estimate, of that portion of the lava that was precipitated into the sea. It is assumed also that no lava was ejected except what was drawn from Kilauea; and that no accessions were made to the stock in that reservoir during the progress of the eruption by fresh emissions from the abysses beneath; the first of which was possible and the last certain, and on a great scale. The estimate must necessarily be in a large degree conjectural; but if conformed to the data furnished by Captain Wilkes, must greatly transcend Mr. Dana's calculation. Captain Wilkes represents the breadth of the stream at its entrance into the ocean as three-fourths of a mile, or 3,960 feet; and the rush of the ourrent to the sea as at the rate of 400 feet an hour. Let us suppose the breadth of the column precipitated into the sea to have been 3,500 feet, its average depth 10 feet, and the length of the current that made the plunge in twenty-four hours, 9,000 feet; the mass, at that rate, precipitated into the ocean in twenty days, would be 6,300,000,000 cubic feet; to which, if the mass remaining on the surface, as estimated by Mr. Dana, 5,018,000,000, be added, they will form an aggregate of 11,318,000,000 cubic feet. If to these the proportion he supposes to have been absorbed by fissures be added, the whole sum will be near 20,000,000,000.

two miles long, and over a mile wide at base."-Dana's Geology of the U. S. Ex. Expedition, pp. 188-192.

The materials of the strata, however, were not thrown up from the interior in the form of lava-as they exhibit no marks of fusion-but of mud or a liquid tide, much like that, probably, which is ejected by the mud volcanoes of Italy, South America, and the Crimea. It seems probable that the first volcanic ejections were neither in the form of molten lava, nor attended with flames or excessive heat. If materials like those of the granitic masses which now constitute the general floor on which the stratified and volcanic rocks rest, originally formed the exterior of the globe, as their crystallization has taken place since their creation, they may be supposed to have existed at first in the form of particles, and were not improbably at the surface promiscuously mingled with each other, so as to form on the first continents and islands, a proper soil for the plants which were made to spring from them. As all the rocks, indeed, of which we have any knowledge, whether crystalline or stratified, have been formed since the creation of the elements of which they consist, we may justly assume that the surface of the earth to the depth which they now occupy, whatever that may be, was in its primitive state, in the form of dust, or without cementation in hard masses. If such was its state, the water of the

ocean would naturally have descended into it, and as long as it met with no other substances than those that constitute granite, as it would have excited little more chemical action than sea water now does on pulverized granite, its chief effect would have been simply to moisten and soften the mass, and render it susceptible of a more easy displacement when subjected to the impulse of a powerful force from beneath. On the supposition, then, that the water descended to a depth equal to that of the present volcanic fires, which is, probably, at least fifteen or twenty miles below the surface, ere it came in contact with elements like iron, for example, and sulphur, which it could excite to powerful chemical action, and that it was then decomposed, a violent heat developed, and vast volumes of expansive gases generated; the effect would have been an upheaval of the softened mass at the points where that action became energetic, and at length the opening of a passage to the surface, by chasms extending, perhaps, long distances, through which the imprisoned forces beneath would have found vents; and the main discharges from which, at first, would obviously not have been molten lava, nor mud raised to a great heat, but the softened earth itself nearest the surface, and subsequently from greater depths. All the force of a powerful volcano may thus be supposed to have been employed for a long time in the seasons of its activity,

in the propulsion to the surface of such unfused materials as form the great elements of the strata, ere burning lava began to be ejected; and this supposition is corroborated by the fact, that it was not till the primary and secondary strata had been formed that the igneous rocks began to appear on the surface.

Another important effect of such a process would have been, that that portion of the earth's surface which was expanded upwards beneath the ocean, would have been exposed by its elevation to the violent action of waves and tides, and currents, and swept off and spread, like that ejected from the depths below, over the surrounding surface. On the intermission of such an eruption, the chasm would speedily have been obliterated by the action of the waters on the softened mass, and soon, perhaps, no other indications of it remained, than the greater thickness near it of the stratum it had formed, than at a distance; as strata usually thin out regularly from the point or line where they attain their greatest depth.

Views very similar to these were several years since suggested by Mr. Bakewell, an eminent English geologist, for the purpose especially of accounting for the limestone and chalk formations. Thus, he says:

"In referring to the vast magnitude of ancient volcanoes,

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