twelve revolutions about the fulcrum, and the varying attraction of the moon, for the velocity of revolution of the part farthest from the moon will be the greatest; and thus the part farthest from the moon will, if fluid, bulge, or be prolated, by the greater centrifugal force, while the part nearest the moon will be bulged or prolated in the opposite direction, by the greater attraction or centripetal force, and thus we have a simple and demonstrable explanation of the two lunar tides, one on each side of the earth; a subject that has been the text of so much mathematical circumlocution and confusion. In like manner the solar revolution will prolate the earth in the direction of the radius of revolution, and produce the solar tide, which must coincide with the lunar prolation twice during each revolution about the fulcrum, producing the spring tides, and by opposing positions, the neap tides. Each rotation of the earth will bring each meridian under the lunar and solar tides twice, and thus we must have 706 lunar and solar tides per annum. All the complexity about sidereal and synodical revolution of the moon, and solar and sidereal rotation of the earth, is removed by these descriptions, considered in reference to proposition 19. It includes the whole story of the moon's rising and setting at different hours from the sun, and other minor phenomena, which space will not permit me to specify. As an example of the mental confusion that the usual mode of describing the moon's motions produces, I may refer to the mistake that the moon presents all her sides twelve times during the year. This is not the case. The sun sees twelve circumferations, but any observer outside her orbit sees thirteen. Even Herschell makes a similar mistake. On page 324, paragraph 528, of his "Outlines of Astronomy," (edition of 1849,) in describing the real curve of the moon about the sun, he tells us that there are thirteen of what he not very accurately calls undulations upon the moon's ellipse. The fact is, that there are only twelve of these extra convexities, corresponding to the twelve circumferations about the earth, the thirteenth convexity is the great ellipse itself, the path of circumferation about the W. M. WILLIAMS. sun. Birmingham, Midland Institute, March 12, 1857. UNCONSCIOUS INFLUENCE.-The following striking instance of unconscious influence was told to me a short time ago by a clergyman. He said, "at the grammar school at which I was educated, there were, not many years ago, two boys who, to the casual observer seemed to present in every respect a most striking contrast; one whom we will call Hardy, was strong, brave, and active; while the other by name Clarke, was a gentle, retiring little fellow, who was generally made a butt of, and bullied a good deal by the other boys, and not the least by Hardy. Clarke, however, was a regular teacher in a Sunday School, and it happened one Sunday, that as he was walking with the boys to church, they pasɛed the house where Hardy lived, and where, unknown to Clarke, he was watching them from one of the windows. Well,' said he to himself, if young Clarke, whom every one despises, is a teacher in a Sunday school, what must I be?' He immediately fell down on his knees, and prayed, for the first time in his life, that God would change his heart, and make him fit to serve Him." That prayer was heard, and he is now labouring as a curate in a large parish; while Clarke, who was the unconscious means of his conversion, is being educated at one of our Universities as a missionary, and he did not know till many years afterwards, how the change was wrought in Hardy, who now became one of his firmest friends. "I can vouch" said my friend, "for the truth of this anecdote, for one of these boys was my own brother."-Church of England Sunday School Magazine · GEOGRAPHY.-No. 3. HE study of Physical Geography is one that embraces a wider field of observation than any other portion of this subject, and at the same time both borrows and reflects a light upon many other sciences, such as geology, history, and ethnology. It is therefore peculiarly interesting and instructive, and deserves to be examined with great attention. Perhaps, at first sight, it may be thought that we are claiming too wide a sphere for our present subject, but we will endeavour to bring forward proofs of the reality of our statement; before doing so, however, we must request the student to turn his attention to the present distribution of land and water over our globe, where he will find not only many points of great interest, but many also which will make him bow with reverence and gratitude before the Author of all good, who has shown such consummate wisdom and mercy in the creation of the globe on which we dwell. About seven-tenths of the earth's surface are covered with water, which is not, however, distributed equally-land predominating in the northern hemisphere, water in the southern: but to prevent the water of this immense southern ocean unduly encroaching upon the land, the mountain chains seem placed as a natural bulwark-those of America and Asia being arranged in a species of irregular arch; and it is not improbable that if we could connect the mountains of Arabia with those of Abyssinia and Central Africa, they would form a continuation of the same figure-the whole being arranged round the shores of the great ocean in a species of semicircle, corresponding to that formed by the shores of the three continents, and thus becoming the common mighty bulwark of nature against the encroachments of the sea. This is one office of these mountain ranges; but many of them have other and more conspicuous duties to perform in the economy of nature, as M. Guizot has convincingly proved in the following passages :-" Mountain chains are great condensers, placed here and there along the continents, to rob the winds of their treasures, to serve as reservoirs for the rain waters, and to distribute them afterwards, as they are needed, over the surrounding plains. Their wet and cloudy summits scems to be untiringly occupied with this important work. From their sides flow numberless torrents and rivers, carrying in all directions wealth and life.' The chain of the Andes, "the great backbone" of the new world, well exemplifies this. "It is situated not far from the western border of America; and to the east of this vast range are extensive plains, with interspersed secondary mountain ranges; and this peculiarity of conformation has a most important and necessary relation to its climatic peculiarities. The trade winds from the Atlantic in their progress first reach the eastern slope, where the secondary chains of mountains condense part of the moisture in refreshing showers, and, finally, coming in contact with the great and elevated principal range, the air is robbed of most of the vapours which remain. Hence a continual flow of water down the eastern slope, clothing that fertile *Earth and Man. region with the richest vegetation, and giving it the largest river system in the world. A necessary result of this influence exerted on the moist trade wind in its progress to the west is, that by the time it reaches the western side of the Andes nearly all its moisture has been lost, and the line of coast on the Pacific presents the character of an arid desert. Now let us imagine a different arrangement of surface; the mountain chain transferred to the eastern instead of occupying the western side; the consequence would have been that the Atlantic trade wind must have had its progress arrested, and its vapours condensed at a comparatively early part of its course; the ocean giving up a portion of its waters to the passing wind, would have received them back again at no great distance in space, and after a short lapse of time; no extensive river systems could have possibly existed as at present; in a word, the whole influence of the genial wind would have been lost." The lands comprising the old and new worlds present some striking contrasts, and at the same time some curious analogies. They stand at right angles to each other; the new world rises perpendicular to the equator, the old parallel to it. The southern ends of both terminate in a high and rocky point, having submarine prolongations indicated by shoals and islands; while they both widen towards the north. On the east of their southern extremities they have each a large island or group of islands, and each has a large gulf to the west. The Atlantic Ocean presents the characteristics of a valley. It is as if the flow of water had been directed first towards the north east, then towards the north west, and then again towards the north east. The parallelism of the coasts north of ten degrees of south latitude, the projecting and re-entering angles-the conversity of Brazil opposite the gulf of Guinea-that of Africa to the gulf of Mexico, all favour this view. The consideration of so curious a fact leads us to reflect on the changes that our globe has undergone, and which are revealed to us by geology. In the pages of "the great stone book" we find indisputable proofs that the waves of the ocean have once and again rolled over the land we now tread beneath our feet; that here there were majestic forests; there vast inland lakes; that there was a time when mighty icebergs, bearing in their stern embrace huge blocks of stone, floated over the inland counties of our own land; that the frozen deserts of Siberia were once clothed with forests, in which the mammoth could find food and shelter. Each page tells us that our earth is nature's kaleidoscope, ever beautiful, yet ever changing, and bidding us remember that as what has been is now no longer, so what is now shall in its turn cease to be when time shall be swallowed up in eternity. But the changes which geology shows us to have already taken place, are still going on. Volcanic and diluvial action knows no rest. The submergence of Atlantis, as related by Plato, is not a solitary fact; other lands have sunk and risen; that of Norway for example, of which the gradual and yearly rise above the level of the sea has been correctly ascertained. A more curious example, however, may be found in the ruins of the temple of Prizzuoli, near Naples, the three remaining large columns of which present a singular appearance. Throughout a part of their height, commencing at nearly eleven feet above the floor of the temple, and continuing about eight feet, they are perforated in all directions by a species of boring marine animal, the modiola lithophaga of Lamark, which still exists in the adjacent parts of the Mediterranean, proving that the temple had been submerged into the sea to that height, and subsequently again elevated; the absence of perforation in the first eleven feet being accounted for on the supposition that the whole area of the temple was filled, either from a shower of volcanic ashes or from some other cause, up to a certain height; and this idea is rendered the more probable from the fact, that when these ruins were re-discovered they were again in a great degree buried, and required excavation. This change in the relative level of land and sea is the more remarkable, because about half a mile along the sea shore towards the west, and standing at some distance from it in the sea, are the remains of columns and buildings which bear the names of the temples of the nymphs and Neptune, the tops of the broken columns being nearly on a level with the surface of the water, which is about five feet deep. But it is not with geology alone, as we have already stated, that physical geography is so intimately connected, It may be pressed into the service of history with equal effect. Let us take a single example. Sacred history narrates to us the occurrence of the seven years of plenty, succeeded by seven years of famine, that took place in Egypt during the period of Joseph's administration. Now the physical geography of that country throws a curious light on this subject, by suggesting the natural means that were probably employed by the Almighty for this purpose. On various parts of the cliffs in Nubia and Ethiopia, as at Hummeh and Senneh, &c. Dr. Lepsius observed, in the year 1843, a number of ancient registries, marking the annual overflow of the Nile, their average height being at all points thirty feet above the highest level ever attained by the present yearly overflow. Soon afterwards Sir George Wilkinson, travelling over the same district for the purpose of investigating these curious inscriptions, made a singular discovery in physical geography, namely, that at the southern part of this district there were vast flats of Nile mud, many miles across on both sides of the river; spots in which are still cultivated by means of channels, though some of them are nine miles distant from the utmost level ever reached by the present annual overflow. The same appearances he traced downwards from the plains of Ethiopia, through the narrow valley of Nubia, over the cataracts of Syene, and as far as the red sandstone rock which crosses the Nile at Djebel Silsili. Below this point they ceased altogether, the Nile through the rest of its course to the sea having met with no perceptible change of level through the many ages during which its valley has been inhabited. It is clear from these facts that in the days of the kings who have engraven their registries on the rocks, the waters of a vast lake covered the plains of Ethiopia from the very mouth of the Astaboras, the last feeder of the Nile to the eastward, and stretched in an estuary to Djebel Silsili. This is Sir Gardiner Wilkinson's own inference. Did it need confirmation, we have it in the circumstance that the Nile itself, before its junction with either of its western feeders, retains precisely the same character along the whole of that part of its course through central Africa with which we have lately become acquainted, frequently expanding into lakes. Egyptian myths referred to the same circumstance, the priests telling Herodotus that the Nile came from the ocean, and flowed into the ocean again; the fact being, as shown by physical geography, that the Nile, when first known to the Egyptians, flowed from a great lake, mistaken by them for the ocean. This lake by some means became discharged, and we are entitled to demand from history an account of the effects such an event must have produced; and these we find narrated by Moses in his account of the seven 1 years plenty and famine. What produces this discharge is another question, though we may easily conceive a natural cause: such as an abundant overflow one year, which by raising the level of the lake might occasion it to wear down its barriers and pour upon the plain below part of its own waters, as well as those of the overflow. This draining of the lake would be a gradual process, and might easily be extended over a period of seven years; and as we know that the fertility of Egypt depends on the amount of its yearly inundation, this unusual increase of the waters would produce an unusual amount of plenty. When all this lake water was drained off, the reverse would take place. The blue Nile would have to force its unassisted way through the now watery mud of the lake's bottom; would spread over its surface, becoming absorbed and evaporated, and hence much less would be carried down to the opposite issue from the lake, and a period of scarcity would ensue, continuing until the river had worked itself a new channel, and then the yearly overflow would appear as usual. We now come to the third and last point of our inquiry, the connection between physical geography and ethnology; and this appears self-evident. The nature of a country determines the character of its inhabitants. It is no mere chance that the native of Africa or India is black, the European white. They are so because they are thus fitted for the countries where they dwell. It is no mere accident that makes the white man enterprising and delighting in toil and struggle, while the Hindoo is passive, indolent, and enduring. It is climate that produces their respective characters. The European would starve did he not earn his bread by the sweat of his brow, and the reward of his daily toil is a love of toil, both physical and intellectual. The tropical sun, on the other hand, forbids the exertion, while it nullifies the necessity of this constant labour; and hence the physical and intellectual character of the nations is formed by the daily habits and occupations of the various individuals of whom it is composed. We cannot conclude this subject better than by giving the following passages from M. de Lamartine,* in which he graphically points out the influence of nature in forming the character, and shows us how the scenes in which our childhood has been passed, throw their colouring over all our after lives. "Our tastes depend on the first view which nature presents to our eyes in the places of our birth, especially when these views are majestic and infinite, like mountains, sea, and sky. Our imagination is but the echo and reflection of the scenes which originally struck us. The first looks of Columbus, while an infant, were upon the heaven and the sea of Genoa. Astronomy and navigation soon directed his thoughts to the spaces thus spread before his eyes. He peopled them in his imagination, before he filled their charts with continents and islands." : Again, when speaking of Cromwell, we find the following passage:"Robert Cromwell, father of the future sovereign of England, brought up his family in poverty, on a small estate upon the banks of the river Ouse, called Ely. The poor, rough, and unyielding nature of this moist country, the unbroken horizon, the muddy river, cloudy sky, miserable trees, scattered cottages, and rude manners of the inhabitants, were well cal *See Lamartine's Celebrated Characters. |