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THE

PURSUIT OF KNOWLEDGE

UNDER DIFFICULTIES;

ILLUSTRATED BY ANECDOTES.

CHAPTER I.

Introduction. Newton; Galileo; Torricelli; Pascal; Prince Rupert ; Montgolfire; Self-education.

WE are about to select from the records of Philosophy, Literature, and Art, in all ages and countries, a body of examples, to shew how the most unpropitious circumstances have been unable to conquer an ardent desire for the acquisition of knowledge. Every man has difficulties to encounter in this pursuit; and therefore every man is interested in learning what are the real hindrances which have opposed themselves to the progress of some of the most distinguished persons, and how those obstacles have been surmounted.

The Love of Knowledge will of itself do a great deal towards its acquisition; and if, it exist with that force and constancy which it exhibits in the characters of all truly great men, it will induce that ardent, but humble spirit of observation and inquiry, without which there can be no success. Sir ISAAC NEWTON, of all men that ever lived, is the one who has most extended the territory of human knowledge; and he used to speak of himself as having

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been all his life but "a child gathering pebbles on the sea-shore"-probably meaning by that allusion, not only to express his modest conviction how mere an outskirt the field of his discoveries was, compared with the vastness of universal nature, but to describe likewise the spirit in which he had pursued his investigations. That was a spirit, not of selection and system-building, but of childlike alacrity, in seizing upon whatever contributions of knowledge Nature threw at his feet, and of submission to all the intimations of observation and experiment, On some occasions he was wont to say, that, if there was any mental habit or endowment in which he excelled the generality of men, it was that of patience in the examination of the facts and phenomena of his subject. This was merely another form of that teachableness which constituted the character of the man. He loved Truth, and wooed her with the unwearying ardour of a lover. Other speculators had consulted the book of nature principally for the purpose of seeking in it the defence of some favourite theory; partially, therefore, and hastily, as one would consult a dictionary: Newton perused it as a volume altogether worthy of being studied for its own sake. Hence proceeded both the patience with which he traced its characters, and the rich and plentiful discoveries with which the search rewarded him. If he afterwards classified and systematized his knowledge like a philosopher, he had first, to use his own language, gathered it like a child.

It is, indeed, most instructive to all who are anxious to engage in the pursuit of knowledge (and is therefore properly introductory to the general subject we are about to treat), to consider the manner in which both this great man and many others, possessing a portion of his observant and inventive genius, have availed themselves, for the enlargement

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of the boundaries of philosophy, of such common occurrences as, from their very commonest, had escaped the attention of all less active and original minds. We are not now speaking of such lucky discoveries as mere chance has sometimes suggested, even to the most inattentive understandings. How far we are indebted to this source for many of those ordinary arts, the origin of which is lost in antiquity and fable, it would not be very easy to determine. The accounts relating to such subjects have been principally handed down to us by poetry and popular tradition, both which are lovers of the mysterious and the marvellous. Hence, there is abundant reason to believe that they are much too full of those wonders which strike an unenlightened fancy; and that, instead of the slow and successive efforts by which the arts in question were actually discovered and improved, there has been substituted, in many cases, the more dramatic incident of a sudden inspiration, merely for the sake of effect. Nay, in those times, the discoverer himself might probably be not unfrequently the first to contrive and spread the fiction; preferring, as he would in all likelihood do, the credit of being the chosen transmitter of supernatural communications to his fellow-mortals, to that of excelling those around him in such mere human and unvalued attributes as philosophic sagacity and patience. Add to this, that the legend of a mystical origin was not only the best recommendation by which any invention could, in the early ages of the world, be introduced to the notice of men; but, perhaps, under the tyranny of a jealous and engrossing superstition, was almost a necessary passport to its reception. However this may have been, it is worth remarking that the current tales had probably some share in leading away the spirit of antiquity from that investigation and application of facts, from which

chiefly has arisen the glory of the philosophy of modern times. This was a necessary consequence of stripping observation and experiment of their due honours, by substituting speculation in their place. The ancients thought, erroneously, that discoveries were to be made by pursuing a train of conjecture, instead of ascertaining results; and thus, whatever patients and labour philosophers might exercise, it came to be popularly thought that discoveries were dependent upon chance, because the steps from one train of speculative reasoning to another could not be traced with the same ease as we now trace the progress of any experimental research.

But, of all sorts of observation, that which exhibits the most penetrating and watchful philosophy is, when, out of the facts and incidents of every-day experience, a gifted mind extracts new and important truths, simply by its new manner of looking at them, and, as it were, by the aid of a light of its own which it sheds upon their worn and obliterated lineaments. From one of these simple incidents did Sir Isaac Newton read to the world, for the first time, the system of the universe. It was in the twenty-third year of his age that this extraordinary man was sitting, as we are told, one day in his garden, when an apple fell from a tree beside him. His mind was perhaps occupied, at that fortunate moment, in one of those philosophical speculations on space and motion which are known to have, about this time engaged much of his attention; and the little incident which interrupted him was instantly seized upon by his eager spirit, and, by that power which is in genius, assimilated with his thoughts.* The existence of gra

* This anecdote is given by Dr. Pemberton, the friend of Newton, as well as by Voltaire, who states that he had it from Newton's niece. See Life of Newton (Library of Useful Knowledge), p. 5.

vitation, or a tendency to fall towards the centre of the earth, was already known, as affecting all bodies in the immediate vicinity of our planet; and the great Galileo had even ascertained the law, or rate, according to which their motion is accelerated as they continue their descent. But no one had yet dreamed of the gravitation of the heavens,-till the idea now first dimly rose in the mind of Newton. The same power, he said to himself, which has drawn this apple from its branch, would have drawn it from a position a thousand times as high. Wherever we go, we find this gravitation reigning over all things. If we ascend even to the tops of the highest mountains, we discover no sensible diminution of its power. Why may not its influence extend far beyond any height to which we can make our way? Why may it not reach to the moon itself? Why may not this be the very power which retains that planet in its orbit, and keeps it revolving as it does around our own earth? It was a splendid conjecture, and we may be sure that Newton instantly set all his sagacity at work to verify it. If the moon, he considered, be retained in her orbit by a gravitation towards the earth, it is in the highest degree probable that the earth itself, and the other planets which revolve around the sun, are, in like manner, retained in their orbits by a similar tendency towards their central and ruling luminary. Proceeding then, in the mean time, upon this supposition, he found by calculation, and by comparing the periods of the several planets and their distances from the sun, that, if they were really held in their courses by the power of gravity, that power must decrease in a certain proportion, according to the distance of the body upon which it operated. This result he had already anticipated from the consideration that, although we could not detect any such diminution within the comparatively small distance

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