THE Book of Nature has, for thousands of years, been displayed to the gaze, the admiration, and the delight of mankind. In great and glorious characters, it testifies to the wonderful power and goodness of its Divine Author: even the meanest or the uncomeliest thing in existence declares the infinite wisdom of its Creator.

In all times and in all places man has sought to understand the language of Nature, and thousands have applied themselves to its study with perseverance, energy, and profound attention. The exertions of the most intellectual and ingenious of men have been exercised, in rendering the contents of this great volume intelligible and accessible to those who seek in its wonderful page for instruction and wisdom. These labours, however, were not crowned with complete success: there are in this book still many marks and signs, even whole pages, which we do not understand, which appear so doubtful or obscure, that we can only guess at their meaning, or conjecture what may be their connection with other portions of the same perfect work.

But as it is only after we have deciphered the separate characters that we discover the meaning of an ancient inscription, so we progressively advance from the knowledge of individual facts and simple objects, to the recognition and comprehension of the general laws of Nature on which they depend.

The efforts of the early students of Nature were solitary, interrupted, and uncombined, and therefore they led to no important results. A subject so full of marvel and mystery can only be successfully prosecuted when men are in the possession of leisure, and when they enjoy the blessings of peace. But these circumstances we rarely find to have been the lot of the learned and the wise, the distinguished men of ancient times. In the history of the earlier nations and empires we learn that the few who directed the destinies of the people at large were so much occupied, either in acquiring or in adjusting political power, that only a limited number of favoured individuals, here and there, had leisure to cast a few hasty glances on Nature.

People were then fully engaged in providing for their mere physical wants; civil order had to be established, and life and

property to be secured. When wars and other calamities left them a breathing time, this was chiefly and necessarily spent in the performance of their legislative and religious functions.

Hence the sciences cultivated in the more ancient times were those of civil polity, law, and religion; and to all these, but especially to the last, the fine arts were more conducive than natural science, and were consequently more successfully cultivated.

Our sketch of the progress of science is divided into that of the earliest, the middle, the modern, and the present age.

Earliest Ages.-The ancients were content to use and to enjoy the gifts of Nature, but had little desire to know their causes or their effects. They had everything to learn. Their usual employments were hunting and fishing, and to these were subsequently added the tending of cattle and the tillage of the soiloccupations which supplied food and clothing, the prime necessaries of life. Hence, in consequence of their daily intercourse with Nature, they noticed many facts and phenomena which, individually and collectively, were useful to their successors.

The Chinese and the Egyptians, who, even at this early period, had formed themselves into well-organised communities, are the earliest nations among which we meet with a large amount of artistic knowledge, as well as regulations which evince that they enjoyed an intimate intercourse with Nature. Yet both of these nations had only attained to intelligence of some individual words or passages of this book; but to an understanding of its spirit and unity, or even to an intelligent apprehension of its less obscure chapters and pages, they never reached.

Middle Ages.-The Greeks, the most civilized people of antiquity, were surrounded by the bounties of nature, which almost spontaneously yielded up to them all the necessaries of life. And thus, not being compelled to wrest from nature her treasures by incessant labour and patient attention, they entered less deeply into her mysteries than might have been anticipated. It was the spirit of nature collectively, and of the human mind specially, that formed the main objects of their observation and reflection; and thus the intellectual, moral, and political sciences were more successfully cultivated than those of nature.

The powerful people of Rome desired only conquests and dominion; their principal occupations were war and legislation; they had no inclination for science, which never thrives unless embraced with love and nursed in the lap of peace. This nation, which made all kingdoms tributary to itself, never dived into the kingdom of nature; and whilst it prescribed laws to all people, it had no idea of the eternal, immutable laws of nature, which overrule the transitory laws of men.

After the overthrow of the great Roman empire, a stormy period succeeded. Prodigious swarms of turbulent people forsook their rugged homes, in quest of new and more congenial habitations. These brought war and desolation in their train; like a destructive flood, they destroyed everything which lay in their track. Art and science bade farewell to Europe, and sought and found an asylum in the more peaceful countries of Asia. While Europe was torn to pieces by savage men, science was cultivated and expanded in Arabia, and much valuable knowledge was brought thence by the Crusaders.

Modern Ages.-Both the external and internal circumstances of Europe became gradually more favourable to the promotion of science. The Christian faith, strengthened and cemented by the testimony and the blood of martyrs, united the nations in defence of their country and common religion, assailed by the irruptions of foreign barbarians. The empire of Germany, founded on the ruins, and composed of the relics of Roman power and civilization, grew up into a permanent and powerful refuge for art and science. Wars and warlike expeditions were still frequent, yet in the seclusion of the monastic establishments, and within the walls of strong, fortified cities, science and art, trade and manufactures, found a safe abode, and were cultivated with energy and success. As men were connected by the bond of proximity and interest, their wants multiplied as their means of supplying them were increased; and the effects of combination and concentration were a more abundant supply of the treasures of nature. There were, besides, other causes co-operating in the ampler diffusion of natural science.

The discovery of printing afforded the facility of preserving and transmitting every invention, experiment, and observation; and the discovery of America not only displayed to the wondering inhabitants of Europe a multitude of curious and remarkable objects, which not merely excited their curiosity, but enkindled the passionate desire of more extensive discovery and more accurate examination.' In England, Scotland, Italy, France, and Germany, they founded universities; establishments in which all the sciences were sedulously cultivated by the most distinguished scholars of that age. The connection of medical and physical science was especially favourable to the promotion of the latter, which, from the earliest ages, has been considered as the sure foundation of medical knowledge and practice.

Present Age.-Armed with the experience of the past, and favoured by a lengthened duration of peace, the present age is more distinguished for scientific pursuits than any former period of the world's history. The more important nations of Europe,

during the greater part of half a century, have sheathed their swords, so long drawn against themselves; and England, France, and Germany, no longer emulate each other in the bloody works of destruction, but strive for the mastery in science, arts, and manufactures. Many of the most eminent and ingenious men have applied themselves exclusively to the study of nature. They were endowed with a keen perception of the essential importance of the physical sciences in philosophy, medicine, agriculture, arboreculture, and manufactures. Under a combination of favourable circumstances and of associated efforts, science has lately made gigantic progress.

In Germany, the General Association of Naturalists was first established, and every year they meet to excite and encourage each other in their labours, to extend the empire of science and the love and knowledge of nature. The British Association for the Encouragement of Science meets annually for similar purposes. From neighbouring nations, and even from the most distant parts of the world, there is a continual intercourse, or scientific commerce carried on, which has a direct tendency to awaken the energies of men, as well as to enlarge their knowledge and excite their curiosity.

The science of the present day has no mysterious secrets which she carefully or churlishly conceals; freely and generously bubble unceasingly her fountains for every one who approaches her with the noble thirst of knowledge.

Happy youths of the present age, whose cradle was rocked under the shadow of the peaceful olive, take advantage of the favourable circumstances of the times, and acquaint yourselves with nature! For, as the man who learned a new language was believed by the ancients to become possessed of a new soul, so man acquires a new sense with the acquisition of every new branch of natural science.-SCHOEDLER'S' Book of Nature.'

THE first thing impressed on us from our earliest infancy is, that events do not succeed one another at random, but with a certain degree of order, regularity, and connection-some constantly, and, as we are apt to think, immutably-as the alterna

tion of day and night, summer and winter; others contingently, as the motion of a body from its place, if pushed, or the burning of a stick if thrust into the fire. The knowledge that the former class of events has gone on, uninterruptedly, for ages beyond all memory, impresses us with a strong expectation that it will continue to do so in the same manner; and thus our notion of an order of nature is originated and confirmed.

If everything were equally regular and periodical, and the succession of events liable to no change depending on our own will, it may be doubted whether we should ever think of looking for causes. No one regards the night as the cause of the day, or the day of night. They are alternate effects of a common cause, which their regular succession alone gives us no sufficient clue for determining. It is chiefly, perhaps entirely, from the other or contingent class of events that we gain our notions of cause and effect; from them alone we gather that there are such things as laws of nature. The very idea of a law includes that of contingency. "Si quis mala carmina condidisset, fuste ferito; if such a case arise, such a course shall be followed,-if the match be applied to the gunpowder, it will explode. Every law is a provision for cases which may occur, and has relation to an infinite number of cases that never have occurred, and never will.

Now, it is this provision, à priori, for contingencies, this contemplation of possible occurrences, and predisposal of what shall happen, that impresses us with the notion of a law and a cause. Among all the possible combinations of the fifty or sixty elements which chemistry shows to exist on the earth, it is likely, nay almost certain, that some have never been formed; that some elements, in some proportions and under some circumstances, have never yet been placed in relation with one another. Yet no chemist can doubt that it is already fixed what they will do when the case does occur. They will obey certain laws, of which we know nothing at present, but which must be already fixed, or they could not be laws. It is not by habit, or by trial and failure, that they will learn what to do. When the contingency occurs, there will be no hesitation, no consultation; their course will at once be decided, and will always be the same if it occur ever so often in succession, or in ever so many places at one and the same instant.

This is the perfection of a law, that it includes all possible contingencies and ensures implicit obedience, and of this kind are the laws of nature. This use of the word law, however, our readers will of course perceive has relation to us as understanding, rather than to the materials of which the uni