and the unspherical form of the internal crust, a great difference of temperature is observable at certain depths in different places; the greatest of which is noticed in the mines of Charlies hope and Poullaonen, the former being one degree for twenty-two feet, and the latter one degree for one hundred and fifty-seven feet. In New-Jersey it has been found that the variation is one degree for seventy-one feet. In England, at the depth of two hundred and fifty fathoms, the temperature is seventy-one degrees, whilst at the surface it was forty-nine degrees. The increase in Peru is in the proportion of ten degrees for four hundred and ninety-five feet, and in Edinburgh the same for two hundred and sixty-eight feet. The annual temperature, at a depth of ninety feet, at Paris does not vary one fifty-fifth of a degree, from fifty-two degrees, and at other places, also, mercury is not affected by atmospheric influence during the year, at determinate depths. So this is considered the mean temperature of the place. The mean temperature of the Mississippi valley is the same as in the same latitudes on the Atlantic, though without the same extremes. The summers are colder, and the winters warmer in the southern hemisphere, when water predominates, than in the northern; owing, as we have before observed, to the difference of land and water and there is thirteen times more land on the north than on the south of the equatorial line, but to latitude forty, either north or south, no great variation is to be noticed. In ascending from the surface, local circumstances are found to influence the degrees of temperature materially at different heights; so that the changes on the surface of the earth, and therefore the means of radiating heat, account for superficial variations, and perfectly agree with our view of the great internal source of that powerful and to organic life-indispensable element. Estimating the central heat by the increase which we have noticed of one degree for every fifty feet, its temperature must be 418,000. The point of boiling water would then be at the depth of about oneand-a-half miles. We find the phenomena of hot, or thermal springs, the Guysers, etc., accounted for alone by this gradual elevation of the earth's temperature in receding from its surface. Their heat is, of course, in proportion to the depth from which they rise, and this is found in conformity with observation. We have not descended over 3,000 feet below the surface, which is about 30,000 feet from the highest point of Himalaya. If the heat increases in the same ratio below, that it does to the distance of 2,000 feet from the surface, the heat at the depth of about 45,000 feet would melt granitic rocks; hence it might be concluded that this is the average thickness of the crust of our earth. The fact that the temperature of mines was higher than the superincumbent surface, was long since noticed, and also that it was probable that the earth gave off more heat than it received from the sun; but the former was supposed to arise from animal heat, and from the burning of candles, gunpowder, etc. Recent experiments have proved, however, that the daily combustion of two hundred pounds of candles and eightysix pounds of powder, with the heat given out by two hundred and sixty-six men, are insufficient to raise the temperature of a mine one degree. As the lights might yield 0.7, powder 0.10, all would be found to give no more than one fifteenth of the thirty-three degrees of heat in the water. This attempt, like that of asserting the change of our climate to have been sudden, in consequence of which animals,' as many have thought, ⚫ were directed, and fully instructed and empowered, by divine impulse, to change their places of abode,' will not harmonize with the discovery of organic remains, or with existing facts in reference to central heat. Nor will the supposed violent change of the relative position of the earth's axis to the plane of its orbit for this presupposes a fact less rationally accounted for, and less consistent with the particular objects of its advocates, than that so well known to exist-afford a plausible cause for the change of climate in question: beside, it has been shown to be opposed both to philosophy and astronomical observation, not to say the discoveries in fossil geology. By the examination of organic remains, we arrive at the fact, that the greatest heat which our earth has sustained, was during the formation of the earlier secondary rocks, and this may have contributed to the confused manner in which they are found, and animals with them, in what have been denominated transition rocks and that it gradually decreased to the upper tertiary rocks, where it appears to have been about the same as it is now. It is not known that the temperature of the earth has undergone much change within the periods of history: it may be inferred, however, from some Roman writers, and from Ovid's Tristia,' that the climate near the Black Sea was much milder 2,000 years ago than now. Yet Arrago thinks that during this period of time the temperature of the earth has not altered even one-fifth of a degree, as in that event there would have been a corresponding alteration in the length of the days, etc. Hence it will hardly be admitted, with Whiston, that during the early state of man, the heat was such as to inflame his passions,' and render his deeds evil continually,' so that it became necessary that his race should be destroyed; nor with Dr. Ure, that the earth has cooled by the evaporation of the waters of the deluge, and, as a consequence, if the former be true, men's passions have thereby become cooled. There are evidences, nevertheless, that in Siberia, for example, the climate was suddenly changed; for there has been found the fossil elephant imbedded in masses of eternal ice, with the flesh preserved, and, though this is a solitary instance, yet the teeth of thousands, now discovered in good preservation which might not be expected, perhaps, after the lapse of unappreciable time, in a hot climate, together with the fact that many vegetable remains indicate a humid atmosphere at the time of their deposition-afford some evidence of a sudden change in the climate of our earth, and of the probability of a rapid evaporation of water at some period of its history. Still, these phenomena, with many others evidently of a local character and of doubtful origin, cannot induce the opinion that they were the result of the sudden dissipation of the immense waters of a general deluge. Philosophy furnishes no means by which to account for an event so extraordinary; for had so great a body of water been elevated into the atmosphere, the aqueous vapors would have been condensed and again precipitated to the earth, quite as rapidly as they were thrown off. Nor will it be supposed that a solution of the facts in question will be found in the absorption of so great a body of water by the earth. At present, this part of our subject forms an interesting problem with fossilists, though it by no means invalidates the evidence of a central heat, nor that, from the gradual condensation and cooling of the earth's crust, the general climate has not as gradually changed. In whatever light we view an event so important in the history of our world, our opinions should be based on the facts developed by natural science, in which fossil geology thus largely participates. We must confine ourselves to rational inductions from natural truths, or, giving the slip to all natural causes, at once launch into an ocean wide' of credulity, and, without organic or inorganic laws, resolve all things into one only universal cause. If we adopt the latter sweeping conclusion, and assign a general deluge, and the remarkable change which our climate has undergone, to immediate supernatural causes — which, now more than ever, is from necessity adopted in consequence of the discoveries in fossil geology-then is it plain that we have no need of any secondary causes for the explanation of any phenomena, and that, from the earliest history of man, we have been the abject dupes of our own estranged imaginations. Since, so far as the experience of man has gone, he has found natural laws to have been instrumental in the production of cause and effect, at least in all events capable of demonstration, it will be the most safe and prudent course for him to doubt where material evidence is wanting, or where phenomena are irreconcileable with natural truths. Hence, as we have found extraordinary organic remains imbedded in the earth — instead of admitting that they were the result of seeds containing prototypes, with which the earth was miraculously endowed, and which were floated about by the air to distant parts of the world — we have searched and found that they are parts of strange animals which lived and died where they are found. But this conceiving natural laws to have been instrumental in the whole, instead of just so much as we choose to understand of the matter is one only of the many instances where the mind has agreeably set itself afloat in the attempt to reconcile the existence and character of organic relics with preconceived opinions, which facts had no power to disturb. The opinions regarding fossil remains, by those who discovered them among the ancients, have been stated to have been more consistent with fact and late observations, than those during the two preceding centuries. Facts were not then distorted and made to bend to particular theories, but conclusions were intended to appear rational and in conformity with natural events. Hence there is little apology for those who have chosen to invent the most extravagant and unnatural means to account for the existence and deposition of fossil bodies, under certain circumstances. Xenophenes mentions the remains of fishes in the stone quarries at Paros and Syracuse. Herodotus describes the fossil shells in the valley of Egypt, and both of these writers attribute their presence in these places to just and rational causes — viz: that having once been at the bottom of the ocean, they were raised from thence by some internal force. Erastosthenes and Strabo observed similar facts, and gave equally rational accounts of them. Pliny, Tertullian, and many others, also mention the discovery of animal exuvia, and they also refer them to definite natural causes. The latter, however, seems to have been the first who attributed the distribution of these substances to a general deluge. Passing down through the dark ages - during which little or no attention was paid to the discovery of fossil remains to the beginning of the 16th century, when shells were found at Verona, we find first, in 1517, Francastoro, and in 1569, Steno, a Dane then Palissy, a Parisian, in 1580, maintaining correct notions, and controverting the crude opinions of their predecessors on this subject. They demonstrated the folly of supposing these fossil bodies to have been dispersed and embodied in rocks by that event. Rouell was also among the first to prove that shells were deposited as they lived, in colonies, and that dif ferent strata of rocks contained different species of molluscus animals. The fossil shells which were excavated at Verona, in 1517, gave birth to the long train of ridiculous theories which, for two centuries and more, were the sport of the philosophic and superstitious. Some writer says that men will not reason consistently on a subject, until they have exhausted it of its ludicrous theories. It is even so, and our subject stands foremost as an example of the truth of the remark. Some reference was had to the character of these theories in a previous article on this subject, and we could not think of exhausting patience by detailing their number, or noticing their crudity. The difficulty with the Verona shells was, that they were found where it was thought impossible for the sea to have deposited them, and as for the strata in which they were found having been at the bottom of the ocean, and elevated to their present situation by some internal agent, was quite out of the question, if, indeed, it was seriously thought of. Francastora opposed and ridiculed popular opinions, and asserted many of the facts now known as true by fossilists. But he received for his advocacy of truth, and his opposition to nonsense, as men now-a-days do, the bitter enmity of those interested in its propagation. It is not a little pleasing to notice the array of passions and arguments against the man and his philosophic views, by the advocates of plastic nature,' materia penguis a certain fermenting fatty matter in the earth, which formed animals, etc. Among the renowned champions in this controversy was Fallopio, professor of anatomy at Padua, and well known by the medical profession as the discoverer of the fallopian tubes. He taught his pupils from the university chair, that shells were generated by fermentation,' and received their form from the tumultuous movements of terrestrial exhalations!' and that fossil teeth were earthy concretions,' etc. It is said there is a book in the pope's holy keeping in his Museum at Rome, written by Mercati in 1574, having drawings of fossil shells. The talented and orthodox writer puts all speculation at rest by proving, beyond a shadow of doubt, that all these shells were not shells but stones, whose form and location were brought about by the influence of the heavenly bodies! It is impossible for the imagination to keep pace with the extravagancies of theologians, who, being alarmed lest the truth should be known on this subject, invented every thing within the scope of that faculty's latitudinous functions to justify their bigotry or whims, and defeat, rather than convince, those who began to think for themselves. But then, as now, it was found impossible to crush the power and freedom of thought. Still few dared at that time to say that these fossils were not the effects of the deluge. As men began to exercise the privilege of reasoning on what they saw, the truth began to appear. Hook, a mathematician and philosopher, in 1705, successfully opposed and ridiculed the folly and bigotry of former clerical writers, and he also maintained, what is now well known, that species of the fossil animals might be entirely extinct. But this was too much for their credulity and superstition. It was denounced as 'improper' and 'heretical,' as it derogated from the faith, etc. Collections of fossils began to be made during the seventeenth century, but the published descriptions of these, and those subsequently made, partook of the credulity we have before mentioned. As these collections increased, theories respecting them seemed for a time to increase only in extravagance. Gessner was one, who, after this, devoted much attention to this subject. We then have, successively, the published catalogues of the Verona Museum in 1622; Besler's Collection of Wormius, in 1652; of Spinen, in 1663; of Septala, in 1666; and, within the following twenty-five years, the descriptions of those of the King's Museum, Denmark; that of Caltorp, of Kirchen, Gresham College, and of Petier. In latter times, those in Europe were Schwenkfeld, Lachmund, Wagner, and Llwyd, describing the fossils of Silesia, Switzerland, etc. The collection in the University of Cambridge, described by Woodward, was one of the largest and most important at the close of this era -the seventeenth century of which we have been speaking. During the following, or eighteenth century, the history of fossil geology assumes a new aspect, and its details are full of interest; but we shall purposely omit the chronological order of those details, since they are mostly within the reach of the curious, because we shall here study to be brief; and because we shall endeavor to embody, as we have done during the seventeenth, the principal facts and discoveries in the course of our reflections — intended, as they have been and as others will be, to associate at the same time the most useful and novel materials with natural and practical inferences. Still more remarkable and interesting have been the facts and discoveries within the present century, compared with which, those of the earlier history of our subject sink into insignificance. These, with the important conclusions which they have induced, will constitute the subject of a succeeding number. PENITENCE. WHEN Comes the awful tempest through the sky, Peals from the bosom of its parent cloud, Who hath not watched with anxious eye to see The first slow rain-drops falling heavily? Who hath not blessed them, as with quickened rush And bid the pulse of Nature calmly beat again? Is there not such a balm for spirits given, When they have wandered from the ways of Heaven? And gloomy sin, have traced a burning path When Heaven no longer, with indulgent eye, Looks on the frailties of mortality But masters all its vengeance, to be shed In fiery ruin on the sinful head; Then cometh Penitence t' arrest that doom, And her sweet tears are seen, glist'ning amid the gloom. |