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We are hence, I think, justified in the conclusion, that its origin was in the north, and that it was brought and deposited on the surface of this country by currents, which in ancient times flowed from beyond the Lakes to the Gulf of Mexico, and of which it may be regarded as the sign and the effect.
• A more recent formation, than many of the alluvial beds contained within the limits just defined, is the stratum of loam spread over the surface of our hills and valleys in an overlaying position. This appears to be the same, that in the north of Europe is denominated geest, and which Mr De Luc considers as the last deposit made by the sea before its final retreat.' « The deposition of the geest seems to have been the last operation, which the waters of the north performed upon this region, and was of course subsequent to the excavation of the valleys, as no deposit could have remained upon their acclivities, while the agent which formed them continued its action. To this formation belong the great blocks of foreign primitive transition, and old floetz rocks, which have excited in travellers so much astonishment, and which, in one point of resemblance at least, approximate the region south of Erie, Huron, Michigan, and other lakes, so closely to that which stretches from the southern shores of the Baltic Sea.
These masses in the neighborhood of this place, [Cincinnati,] are for the most part solitary, but in the interior of the State it is not uncommon to find them grouped into heaps, which are slightly covered with soil ; and it is, I suspect, an aggregation of this kind, on one of the Islands of Lake Huron, that a British officer mistook for granite in place. The size of these masses extends from that of gravel and pebbles to the diameter of eight or ten feet. The larger blocks are frequently found upon the old alluvial plains, but never, that I have understood, within them. Their geographical range is over the same region with the smaller foreign debris of our valleys, but more limited to the south west.
I have never seen a single block on the opposite side of the Ohio, and am not informed that any have been observed lower than the thirtyninth degree of latitude.
I do not entertain a doubt, that these fragments were enveloped in large fields of ice in a region far beyond the Lakes, and floated hither by the same inundations, that brought down and spread over the surface of this country the geest in which they are imbedded. In the southern parts of this formation they are not found; but this should be attributed to the influence of the climate. The ice, to which they were attached, could not of course pass a certain latitude; and from the great increase of these masses as we advance towards the north, it would seem that many of the icebergs suffered dissolution long before they arrived at this maximum. Future observers will no doubt trace them to their parent strata in the arctic regions, as Von Buck has traced those, which are lodged on the shores of the Baltic. The ice islands of the Atlantic ocean may reasonably be supposed to bring down, and deposit on its bed in the Temperate zone, primordial masses similar to those spread over some parts of this and the European continent. These islands are, I believe, not often seen further south than the fortyfirst degree, vear two degrees north of their southern boundary here. This is probably attributable to the Gulf Stream; but for which, the larger tracts of ice would undoubtedly attain as low a latitude as the southern limits of the primitive blocks in this country; and hence a probable conclusion may be drawn, that the temperature of the northern hemisphere has undergone but little change, since the remote epoch when this part of the continent was for the last time subjected to inundation.
From these facts, and this mode of reasoning, it would seem, that at some former period the ocean flowed over this continent with a current setting from north to south, and that the present features of the earth's surface in these regions have taken their shape and character from the action of this cause. Mr Hayden has pursued the same inquiry, in regard to the rivers and soil on the Atlantic coast, and has come to the same result. The only additional proof, now required, is that mentioned by Dr Drake as having been applied by Von Buck. Let it be established, by observation, that the rocky fragments, deposited throughout the alluvial formation of this country, are of precisely the same kind as the primitive masses in the polar regions of the American continent, and the demonstration will approach a degree of certainty, which will be satisfactory to most minds.
The fifth article in the volume is one of a good deal of interest and value. It contains a series of observations, by Mr John Hamilton, on the Winds, Currents, the Gulf Stream, and the Temperature of the Air and Water in the North Atlantic Ocean. The tables are skilfully constructed, and the observations carry with them every appearance of accuracy. These latter were made during twentysix voyages across the Atlantic, chiefly between Philadelphia and Liverpool. It was Mr Hamilton's object to ascertain, whether any substantial results could be derived from a course of observations of this sort, which should be of uniform and permanent advantage to navigators. In summing up the matter, however, he seems not to be very sanguine, although he clearly shows, that a methodical use of the thermometer, in determining the temperature of the water, will enable the mariner infallibly to tell, after a little practice, when he is in a current, or on soundings. He says that currents at sea are usually from two to four degrees warmer, than the water out of the current. On soundings the water is always warmer than off, although the temperature varies more than in currents, as it depends much on the depth of the water, and the position of the coast. Along the American shore the difference of temperature varies also with the seasous, it being less in summer than in the other seasons.
In navigating the Gulf Stream the thermometer is of essential use. The difference between the temperature on the north side of this current and the sea out of it averages ten degrees; on the south side it is not so much, but never less than five degrees. In summer it is less than in winter. By knowing these data, and by using the thermometer three or four times a day, the navigator may always determine when he enters the Gulf Stream. It is not easy to define the exact limits of this stream, because it is more or less affected by the winds; and after it passes the Grand Bank of Newfoundland it is divided into several branches, the main current proceeding to the south east, and the others to the east and north east. There are counter currents on each side of the Gull Stream, but Mr Hamilton thinks the temperature of these not to be perceptibly different from that of the stream itself. The thermometer, therefore, will not indicate the counter currents; but this is not of much moment, compared with the great utility of the instrument in determining the presence of the stream itself, which, on account of the variableness of the current produced by winds and other causes, is not easy to be ascertained by any mode of calculation. Mr Hamilton says, that many navigators who profess to use the thermometer, profit little by it, because they do not begin their observations till they suppose themselves approaching the Gulf Stream, or soundings, and then, if it happens that they have entered either, the temperature is changed from that of the ocean, and they have no means of an accurate comparison. To be of any use, the observations should be daily, and regular. Were every experienced and intelligent navigator to take the pains,
which Mr Hamilton has done in forming his tables, we doubt not that a series of facts would be collected, which would greatly facilitate the navigation not only of the Atlantic Ocean, but of other parts of the world.
We have next in order a very long paper on the Survey of the Coast of the United States, by Mr Hassler, making nearly one half of the volume. The singular result of the efforts of the government to survey the coast of the United States, has been a source of serious regret to many, and of wonder to all, who have known anything of the subject. thousands have been expended in purchasing instruments, retaining engineers, forming splendid projects, and preparing for great undertakings, we shall forbear to inquire. It is well known, that no visible thing has been done, and that we yet labor under the disgrace of being obliged to resort to the British charts of our coast, as the best that have been made. Holland's Charts, published in England, at the commencement of the Revolution, or copies from them, are still the guides to our seamen, when they would ensure accuracy and safety. The soundings are corrected in Blunt's charts, but the topographical delineations are nowhere executed with so much fidelity as in the old English surveys; and even in the late war, the inhabitants of the coast were frequently surprised at seeing the British vessels of large size sailing boldly into passages and inlets, where no American had ever ventured with the lightest coasting craft. Nothing would contribute more to the success and security of our commerce, than a thorough and minute survey of the coast; on nothing could public money be more profitably, or creditably, expended; and at no time can it be done with more ease and convenience, than at the present. To defer it longer is but to perpetuate the reproach, which past neglect has so justly drawn upon the nation. Much might be said on this subject, in relation to what has been attempted heretofore, to the projects that were in contemplation, and to the history and fate of the elegant and costly instruments, which were procured in Europe, but which are now neglected and useless.
There is a memoir in the volume, written in French, by Mr Jules de Wallenstein, containing an account of Meteorological Observations made by him at Washington, during the VOL. XXII.-NO. 50.
space of one year, from April 1823 to April 1824. Tables of results are also added to the memoir. Whether we regard the accuracy of the instruments, or the scientific skill of the author in using them, we presume Mr de Wallenstein's observations may justly be ranked among the best, which have been made in this country. His instruments were selected by himself in Europe, and constructed by the most eminent artists. They form a complete apparatus for observing the temperature, pressure, and moisture and dryness of the atmosphere. He begins his paper by describing these instruments, and his mode of using them. His barometer was constructed by Fortin, on the most approved principles, and was of the same kind as that employed in the Royal Observatory in Paris; his hygrometer was on the plan of Saussure; he had two thermometers by Lerebours and Fortin, and one by Troughton with Farenheit's scale. These are all briefly described.
The author's most curious remarks are those on the horary variations of the barometer. He gives a concise view of this interesting subject, as it has been treated by Humboldt, Godin, La Condamine, and others. It is not of a nature to be discussed in this place, but we agree with Mr de Wallensteio, that it well deserves the attention of philosophers, and of those who travel for improvement in natural science. He thinks these variations of the barometer are in some way linked with other appearances, the causes of which are yet among the secret things of nature, and supposes it probable, that good observations on the periodical variations of the magnetic needle, electricity, and the barometer, made by such men as Humboldt, La Condamine, Mutis, and Buch, might lead to the discovery that there is some connexion between these phenomena, or at least that one may be explained by another.' Whatever may be thought of this suggestion, it must be confessed, that these topics offer a wide and unexplored field for philosophical research. It will be at once perceived, that the influence of such discoveries must be very great, when it is considered how universal are these phenomena and their causes, and how completely they pervade all parts of physical nature. Nor does the progress of these discoveries seem so difficult, as might at first be imagined, since, as the author remarks, Mutis has already ascer