INTRODUCTIONS TO THE TITLES DESIGNED

FOR THE NEXT FIVE MONTHS.

FOR THE INTRODUCTION

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THE HISTORY OF DENSE AND RARE,

SEE THE HISTORY.

THE HISTORY OF HEAVY AND LIGHT.

ance.

INTRODUCTION.

THE motion of heavy and light was distinguished by the ancients under the name of natural motion. For they saw no external efficient, and no apparent resistMoreover this motion seemed to gain rapidity by its progress. To their contemplation or rather discourse on this subject they added by way of seasoning the mathematical fancy that heavy bodies would adhere to the centre of the earth (even if a hole were made through it), together with the scholastic fiction of the motion of bodies to their own places. And believing that by these positions they had settled the question, they made no further inquiry, except that there was one of them who inquired somewhat more diligently concerning the centre of gravity in different figures, and touching the things which float on water. Nor has one of the moderns contributed anything of consequence; having only added a few mechanical inventions, and even those distorted by his demonstrations. But to speak direct, it is quite certain that a body is affected only by a body; and that there is no local motion which is not excited either by the parts of the body moved, or by the adjacent bodies, or by those contiguous or proximate to it, or at least by those

which lie within the sphere of its activity. Gilbert therefore has not unscientifically introduced the question of magnetic force, but he has himself become a magnet; that is, he has ascribed too many things to that force, and built a ship out of a shell.

THE HISTORY OF THE SYMPATHY AND ANTIPATHY OF THINGS.

INTRODUCTION.

STRIFE and friendship in nature are the spurs of motions and the keys of works. Hence are derived the union and repulsion of bodies, the mixture and separation of parts, the deep and intimate impressions of virtues, and that which is termed the junction of actives with passives; in a word, the magnalia naturæ. But this part of philosophy concerning the sympathy and antipathy of things, which is also called Natural Magic, is very corrupt; and (as is almost always the case), there being too little diligence, there has been too much hope. The effect of hope on the mind of man is very like the working of some soporific drugs, which not only induce sleep, but fill it with joyous and pleasing dreams. For first it throws the human mind into a sleep by the recital of specific properties, and secret and heavensent virtues; whence men are no longer wakeful and eager in searching out real causes, but are content to rest in such kinds of indolence; and then it insinuates and infuses into it innumerable fancies, like so many dreams. Men likewise in their folly expect to become acquainted with nature from her outward face and mask, and by external resemblances to detect internal

properties. Their practice also is very like their inquiry. For the rules of natural magic are such, as if men expected to till the ground and eat their bread without the sweat of their brow, and by an easy and indolent application of bodies to become masters of things. And they are always talking of the magnet, and the sympathy of gold with quicksilver, and a few other things of the kind, and appealing to them as sureties to accredit other things which are not bound by any similar contract. But God has ordained that whatever is excellent shall be won only by labours both in inquiry and working. For my own part, in unravelling the law of nature, and interpreting the relations of things, I shall show somewhat more diligence, not giving way to marvels and wonders, and yet not instituting a narrow or partial inquiry.