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the air from the direction of the countries whose temperatures are so much elevated, may be thought to militate against the inference, that their climates are improved by heat from that source; but the continued stream of air in the region of the trade-winds all round the world, wherever the surface of the earth is uninterrupted by tablelands or mountain ranges, from NE., must have a counterbalancing SW. wind somewhere; for which reason it has long been held, that the south-west winds of the temperate zone compensate or restore the atmospheric equilibrium which a perpetual NE. trade-wind would disturb.

Taking, then, the SW. winds as the return currents of air carried towards the equator by a NE. trade-wind, the influence of the heated air of the Sahara should reach Europe by a SW. wind; then, if we allow that much of the heat received by the air in the desert has assumed a latent form in aqueous vapour during the transit, we should next expect to find that where the aqueous vapour is chiefly condensed, the isothermal lines tend furthest northward, a supposition which agrees well with the position of the isothermal line for 32° temperature on the coast of Norway.

The climate of western Europe may be held to owe its favoured temperatures to two distant sources of heat. The first, and most important, from a tropical sun acting on the air over the greatest desert in the world; the second from the same tropical sun heating the waters of the Carribbean sea. The action of the sun on ground destitute of vegetation is well known to heat the incumbent air with rapidity; in dry bright weather the air over a fallow field in this country is seen agitated by the uprising currents of air; and I have seen a thermometer placed on the soil, and covered with a little powdered dry earth, stand, on 1st August, at 120° Fahrenheit. In the African desert, there is within a short aërial journey of us, a mass of heated air greater than can be found in any other place of the same magnitude. The space of time required for the transmission of this air to Europe must, I fear, remain a matter of conjecture, the probability is that it may reach the latitude of London in 100 hours. The second source of heat, the Carribbean sea, has an area nearly the same as the Sahara, so that there may be an amount of solar influence to transmit to northern regions nearly equal to that from the Sahara.. The gulf stream passes for a course of 1800 geographical miles along the American coast, bathing the shores of places possessing low temperatures for their latitudes, but which are nevertheless influenced by the gulf stream; for, receding from the shore inland, the isothermal line tends to the south; while, for Europe, the gulf stream has to make another journey of 1800 miles, where its influence must be still less than on the American coast,

* Vide Charts by M. Humboldt and Professor Dove.

from which we must infer that very little of the temperature of Europe can be due to the gulf stream. Taking the south-west winds as the counterbalancing currents for the perpetual NE. trade-winds, they cannot derive their heat from passing over the warm water of the gulf stream, for that is not in their tract. Subsequent observation must determine whether our S. and SW. winds derive their heat from what is generated in the form of dry parched air on the African Sahara; for the reasons given, I cannot but help believing that it is so, and that the west coast of Europe enjoys a climate distinguished for its high temperature above all other lands of the same latitude through the influence of the great desert of Africa.

On British Eocene Serpents and the Serpent of the Bible. By Professor OWEN.

A few bones of serpents have been found in the superficial stalagmite, and in clefts of caves, in peat bogs, and the like localities, which bring their occurrence and deposition within the period of human history. None of these Ophidian remains, however, have offered any differences in size or other character from the corresponding parts of the skeleton of our common harmless snake (Coluber natrix.) As yet, no Ophidian fossils have been found in British fresh-water formations of the pre-adamitic or pleistocene period, from which formations the remains of the Mammoth, Tichorrhine Rhinoceros, great Hippopotamus, and other extinct species of existing genera of Mammalia have been so abundantly obtained. Between the newest and the oldest deposits of the tertiary period in geology, there is a great gap in England, the middle or miocene formations being very incompletely represented by some confused and dubious parts of the crag of fluvio-marine origin in which teeth of a Mastodon have been found.

The deposits in which the remains of the large serpents of the genus Palæophis occur so abundantly, carry back the date of their existence to a period much more remote from that at which human history commences. Yet, as the strange and gigantic reptiles that have been restored, and, as it were, called again to life, from times vastly more ancient, realize, in some measure the fabulous dragons of mediæval romance; so the locality on our shore of the English channel in which the Eocene serpents have been found in most abundance and of largest size, recalls to mind, by a similar coincidence, the passage cited by an accomplished and popular historian, in his masterly sketch of the rise and progress of the English nation. "There was one province of our island in which, as Procopius had been told, the ground was covered with serpents, and the air was such that no man could inhale it and live. To this desolate region the

spirits of the departed were ferried over from the land of the Franks at midnight."-Macaulay's History of England, vol. i., p. 5.

The discovery of serpents of different genera and species, some, as e.g. Paleryx, terrestrial, and all manifesting the peculiar and characteristic Vertebral organization of true Ophidia, at a period incalculably remote from that at which we have any evidence of the existence of man, more forcibly recalls our early ideas of the nature and origin of serpents derived from annotations to Scripture which represented them as the progeny of a transmuted species, degraded from its originally created form as the consequence and punishment of its instrumentality in the temptation of Eve.

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"The curse upon the serpent," say the learned Drs D'Oyly and Mant, in the edition of the Bible printed under the direction of the Society for the Promotion of Christian Knowledge, ed. 1823, "consisted, 1st, in bringing down his stature, which was probably, in great measure, erect before this time; upon thy belly shalt thou go,' or, upon thy breast,' as some versions have it: 2dly, In the meanness of his provision, and dust shalt thou eat,' insomuch as creeping upon the ground, it cannot but lick up much dust together with its food."

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The idea of the special degradation of the serpent to its actual form, derived from interpreting the sentence upon it as a literal statement of fact, has been so prevalent as to have affected some of the zoological treatises of the last century. Thus, in the quaint and learned "Natural History of Serpents," by Charles Owen, D.D., 4to, 1742, p. 12, the author, treating of the food of those reptiles, writes," That dust was not the original food of the serpent seems evident from the sentence passed upon the Paradisaick serpent, but the necessary consequence of the change made in the manner of its motion, i. e., the prone posture of its body, by which it is doomed to live upon food intermixed with earth.”

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Dr Adam Clark, commenting more recently upon the record in its literal sense, seeks to elude the difficulties which thence arise, by contending that the Hebrew "Nachash," may be translated Ape," as well as Serpent." But when we find him reduced to the necessity of glossing the text by such expositions, as that to go on the belly, means "on all-fours ;" and by affirming, of the arboreal frugivorous four-handed monkeys, that "they are obliged to gather their food from the ground," we have a lively instance of the straits to which the commentator is reduced who attempts to penetrate deeper than the Word warrants, into the nature of that mysterious beginning of crime and punishment, by the dim light of an imperfect and second-hand knowledge of the divine works.

If, indeed, the laws of the science of Animated Nature formed part of the preliminary studies of the theologist, the futility of such attempts to expound the third chapter of Genesis, viewed as a simple narration of facts, would be better appreciated by him; and if he

should still be prompted to append his thoughts, as so many lamps by the side of the second text, he would most probably restrict himself to the attempt to elucidate its symbolical signification.

What zoology and anatomy have unfolded of the nature of serpents in regard to their present condition, amounts to this: that their parts are as exquisitely adjusted to the form of their whole, and to their habits and sphere of life, as is the organization of any animal which, in the terms of absolute comparison, we call superior to them. It is true, the serpent has no limbs, yet it can outclimb the monkey, outswim the fish, outleap the jerboa, and, suddenly loosing the close coils of its crouching spiral, it can spring into the air and seize the bird upon the wing; thus all these creatures fall its prey. The serpent has neither hands nor talons, yet it can outwrestle the athlete, and crush the tiger in the embrace of its ponderous overlapping folds. Far from licking up its food as it glides along, the serpent lifts up its crushed prey, and presents it, grasped in the death-coil as in the hand, to the gaping slime-dropping mouth.

It is truly wonderful to see the work of hands, feet, fins, performed by a simple modification of the vertebral column in a multiplication of its joints, with mobility of its ribs. But the vertebræ are specially modified, as I have already described, to compensate, by the strength of their individual articulations, for the weakness of their manifold repetition and of the consequent elongation of the slender column.

As serpents move chiefly on the surface of the earth, their danger is greatest from pressure and blows from above; all the joints are accordingly fashioned to resist yielding, and to sustain pressure in a vertical direction; there is no natural undulation of the body upwards and downwards, it is permitted only from side to side. So closely and compactly do the ten pairs of joints between each of the two or three hundred vertebræ fit together, that even in the relaxed and dead state the body cannot be twisted, except in a series of side coils.

Of this the reader may assure himself by a simple experiment on a dead and supple snake. Let him lay it straight along a level surface; seize the end of the tail, and, by a movement of rotation between the thumb and finger, endeavour to screw the snake into spiral coils; before he can produce a single turn, the whole of the long and slender body will roll over as rigidly as if the attempt had been made upon a straight stick.

When we call to mind the anatomical structure of the skull, the singular density and thickness of the bones of the cranium, strike us as a special provision against fracture and injury to the head. When we contemplate the still more remarkable manner in which these bones are applied one over another, the superoccipital, overlapping the exoccipital, and the parietal overlapping the superoccipital, the natural segments being sheathed one within the other, the occipital segment within the parietal one, we VOL. XLIX. NO. XCVIII.-OCTOBER 1850.

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cannot but discern a special adaptation in the structure of Serpents to their commonly prone position, and a prevision of the dangers to which they were subject from falling bodies, and the tread of heavy beasts. I might enumerate many other equally beautiful instances of design and foresight, the whole organization of the Serpent is replete with such-in relation to the necessities of their apodal vermiform character; just as the snake-like eel is compensated by analogous modifications amongst fishes, and the snake-like centipede amongst insects.

But what more particularly concerns us in the relation of the serpent to our own history, is the great and significant fact revealed by palæontology, viz., that all these ophidian peculiarities and complexities of cranial and vertebral organization, in designed subserviency to a prone posture, and a gliding progress on the belly, were given by a beneficent Creator to the serpents of that early tertiary period of our planet's history; when, in the slow and progressive preparation of the earth, the species which are now our contemporaries were but just beginning to dawn; these, moreover, being species of the lowest classes of animals, called into existence long before any of the actual kinds of mammalia trod the earth, and long ages before the creation of man.-A History of British Reptiles, by Professor Richard Owen. Part III., p. 151.

On Lamprey Eels-(Petromyzontida)—and their Embryonic Development and Place in the Natural History System.

There are families in all departments of nature, whose peculiarities call for an investigation of their more general relations rather than of their structural details. The Petromyzons are in this case. Closely allied together and circumscribed in a most natural family, it is a question whether they should be entirely separated from all other fishes to form a great group by themselves, or whether they belong to one of those great divisions in which the individual members differ widely from each other. In other words, should the Petromyzons stand by themselves in a natural classification of fishes, as Prince Canino and Joh. Müller have placed them, or shall we combine them with skates and sharks, as Cuvier has done? To answer such a question, it is necessary to discuss beforehand principles of the utmost importance in the study of natural history, and above all to settle the following difficulty: Is the study of anatomical structure an abso

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