In the late evening of a varied and active life, I offer to the German public a work of which the undefined type has been present to my mind for almost half a century. Often the scheme has been relinquished as one which I could not hope to realise, but ever after being thus abandoned, it has been again, perhaps imprudently, resumed. In now presenting its fulfilment to my contemporaries, with that hesitation which a just diffidence of my own powers could not fail to inspire, I would willingly forget that writings long expected are usually least favourably received.

While the outward circumstances of my life, and an irresistible impulse to the acquisition of different kinds of knowledge, led me to occupy myself for many years, apparently exclusively, with separate branches of science,—descriptive botany, geology, chemistry, geographical determinations, and terrestrial magnetism, tending to render useful the extensive journeys in which I engaged,—I had still throughout a higher aim in view; I ever desired to discern physical phænomena in their widest mutual connection, and to comprehend Nature as a whole, animated and moved by inward forces. Intercourse with highly-gifted men had early led me to the conviction, that without earnest devotion to particular studies such attempts could be but vain and illusory.

ON THE DIFFERENT DEGREES OF ENJOYMENT OFFERED BY THE ASPECT OF NATURE AND THE STUDY OF HER LAWS.

In attempting, after a long absence from my country, to unfold a general view of the physical phenomena of the globe which we inhabit, and of the combined action of the forces which pervade the regions of space, I feel a double anxiety. The matter of which I would treat is so vast, and so varied, that I fear, on the one hand, to approach it in an encyclopædic and superficial manner, and on the other, to weary the mind by aphorisms presenting only dry and dogmatic generalities. Conciseness may produce aridity, whilst too great a multiplicity of objects kept in view at the same time leads to a want of clearness and precision in the sequence of ideas.

But nature is the domain of liberty; and to give a lively picture of those ideas and those delights which a true and profound feeling in her contemplation inspires, it is needful that thought should clothe itself freely and without constraint in such forms and with such elevation of language, as may be least unworthy of the grandeur and majesty of creation.

If the study of physical phænomena be regarded in its bearings, not on the material wants of man, but on his general intellectual progress, its highest result is found in the knowledge of those mutual relations which link together the various forces of nature.

The effect of landscape painting, notwithstanding the multiplication of its productions by engravings and by the modern improvements of lithography, is still both more limited and less vivid, than the stimulus which results from the impression produced on minds alive to natural beauty by the direct view of groups of exotic plants in hot-houses or in the open air. I have already appealed on this subject to my own youthful experience, when the sight of a colossal dragon tree and of a fan palm in an old tower of the botanic garden at Berlin, implanted in my breast the first germ of an irrepressible longing for distant travel. Those who are able to reascend in memory to that which may have given the first impulse to their entire course of life, will recognise this powerful influence of impressions received through the senses.

I would here distinguish between those plantations which are best suited to afford us the picturesque impression of the forms of plants, and those in which they are arranged as auxiliaries to botanical studies; between groups distinguished for their grandeur and mass, as clumps of Bananas and Heliconias alternating with Corypha Palms, Araucarias and Mimosas, and moss-covered trunks from which shoot Dracontias, Ferns with their delicate foliage, and Orchideæ rich in varied and beautiful flowers, on the one hand; and on the other, a number of separate low-growing plants classed and arranged in rows for the purpose of conveying instruction in descriptive and systematic botany.

Plato describes the narrow limits of the Mediterranean in a manner quite appropriate to enlarged cosmographical views. He says, in the Phædo, “we who dwell from the Phasis to the Pillars of Hercules, inhabit only a small portion of the earth, in which we have settled round the (interior) sea, like ants or frogs around a marsh.” It is from this narrow basin, on the margin of which Egyptian, Phœnician, and Hellenic nations flourished and attained a brilliant civilisation, that the colonisation of great territories in Asia and Africa has proceeded; and that those nautical enterprises have gone forth, which have lifted the veil from the whole western hemisphere of the globe.

The present form of the Mediterranean shews traces of a former subdivision into three smaller closed basins. The Ægean portion is bounded to the south by a curved line, which, commencing at the coast of Caria in Asia Minor, is formed by the islands of Rhodes, Crete, and Cerigo, joining the Peloponnesus not far from Cape Malea. More to the west we have the Ionian Sea, or the Syrtic basin, in which Malta is situated: the western point of Sicily approaches to within forty-eight geographical miles of the African shore; and we might almost regard the sudden but transient elevation of the burning island of Ferdinandea (1831), to the southwest of the limestone rocks of Sciacca, as an effort of nature to reclose the Syrtic basin, by connecting together Cape Grantola, the Adventure bank (examined by Captain Smith), the island of Pantellaria, and the African Cape Bon,—and thus to divide it from the third, the westernmost, or Tyrrhenian basin.

INCITEMENTS TO THE STUDY OF NATURE.

We now pass from the domain of objects to that of sensations. The principal results of observation, in the form in which, stripped of all additions derived from the imagination, they belong to a pure scientific description of nature, have been presented in the preceding volume. We have now to consider the impression which the image received by the external senses produces on the feelings, and on the poetic and imaginative faculties of mankind. An inward world here opens to the view, into which we desire to penetrate, not, however, for the purpose of investigating—as would be required if the philosophy of art were our aim—what in æsthetic performances belongs essentially to the powers and dispositions of the mind, and what to the particular direction of the intellectual activity,—but that we may trace the sources of that animated contemplation which enhances a genuine enjoyment of nature, and discover the particular causes which, in modern times especially, have so powerfully promoted, through the medium of the imagination, a predilection for the study of nature, and for the undertaking of distant voyages.

I approach the termination of a comprehensive and hazardous undertaking. More than two thousand years have been passed in review, from the earliest state of intellectual cultivation among the nations who dwelt round the basin of the Mediterranean and in the fertile river districts of Western Asia, to a period the views and feelings of which pass by almost imperceptible shades into those of our own age. I have sought to present the history of the gradually developed knowledge and recognition of the Universe as a whole, in seven distinctly marked sections, or as it were in a series of as many distinct pictures. Whether any measure of success has attended this attempt to maintain in their due subordination the mass of accumulated materials, to seize the character of the leading epochs, and to mark the paths in which ideas and civilisation have been conducted onwards, cannot be determined by him who, with a just mistrust of his remaining powers, knows only that the type of so great an undertaking has floated in clear, though general, outlines before his mental eye.

In the early part of the section occupied by the epoch of the Arabians, in beginning to describe the powerful influence exerted by the blending of a foreign element with European civilisation, I determined the period from which the history of the Cosmos becomes coincident with that of the physical sciences.

In tracing the intellectual progress of mankind and the gradual extension of cosmical views, the period of the Roman universal Empire presents itself as one of the most important epochs. We now for the first time find all those fertile regions of the globe which surround the basin of the Mediterranean connected in a bond of close political union, which also comprehended extensive countries to the eastward. I may here appropriately notice, that this political union gives to the picture which I endeavour to trace, (that of the history of the contemplation of the universe), an objective unity of presentation. Our civilization, i. e. the intellectual development of all the nations of the European Continent, may be regarded as based on that of the dwellers around the Mediterranean, and more immediately on that of the Greeks and the Romans. That which we term, perhaps too exclusively, classical literature, has received this denomination through men's recognition of the source from whence our earliest know ledge has largely flowed, and which gave the first impulse to a class of ideas and feelings most intimately connected with the civilization and intellectual elevation of a nation or a race. We do not by any means regard as unimportant the elements of knowledge, which, flowing through the great current of Greek and Roman cultivation, were yet derived in a variety of ways from other sources—from the valley of the Nile, Phœnicia, the banks of the Euphrates, and India; but even for these we are indebted, in the first instance, to the Greeks, and to Romans surrounded by Etruscans and Greeks.

In my sketch of the history of the physical contemplation of the universe, I have already enumerated four leading epochs in the gradual development of the recognition of the universe as a whole. These included, firstly, the period when the inhabitants of the coasts of the Mediterranean endeavoured to penetrate eastward to the Euxine and the Phasis, southward to Ophir and the tropical gold lands, and westward through the Pillars of Hercules into the “all-surrounding ocean;” secondly, the epoch of the Macedonian expeditions under Alexander the Great; thirdly, the period of the Lagidæ; and fourthly, that of the Roman Empire of the World. We have now to consider the powerful influence exercised by the Arabians, whose civilization was a new element foreign to that of Europe,—and, six or seven centuries later, by the maritime discoveries of the Portuguese and Spaniards,—on the general physical and mathematical knowledge of nature, in respect to form and measurement on the earth and in the regions of space, to the heterogeneity of substances, and to the powers or forces resident therein. The discovery and exploration of the New Continent, with its lofty Cordilleras and their numerous volcanoes, its elevated plateaus with successive stages of climate placed one above another, and its various vegetation ranging through 120 degrees of latitude, mark incontestably the period in which there was offered to the human mind, in the smallest space of time, the greatest abundance of new physical perceptions.