THOUGHTS ON THE NATURE OF THINGS.

I.

On the Division of Bodies, Continuity, and Vacuity.

THE doctrine of Democritus concerning atoms is either true or useful for demonstration. For it is not easy either to grasp in thought or to express in words the genuine subtlety of nature, such as it is found in things, without supposing an atom. Now the word atom is used in two senses, not very different from one another. For it is either taken for the last term or smallest portion of the division or fraction of bodies, or else for a body without vacuity. With respect to the first, these two positions may be safely and certainly laid down; the one, that there is in things a much more subtle distribution and comminution than falls under view; the other, that this is not however infinite nor perpetually divisible. For if a man observe diligently, he will find that the minute particles of things in continued bodies are far more subtle than those in bodies broken and discontinued. For we see that a little saffron infused and stirred up in water will colour a whole hogshead, so as to make it distinguishable even by the sight from pure water. Now this distribution of saffron in the water is certainly more subtle than that of the finest powder, as will be shown if a similar quantity of powder of Brazil-wood, pomegranate flowers, or any highly coloured substance, which has not the sequacity of saffron to spread in liquids and incorporate itself with them, be infused in the same way. It was ridiculous therefore to take those small bodies that appear in the sun's rays for atoms. For these are like dust; whereas an atom, as Democritus himself said, no one ever saw or can sce. But this distribution of things is shown much more wonderfully in smells. For if a little saffron will tinge and infect a whole hogshead of water with colour, a little civet will infect a suite

of two or three large rooms with its odour. And let no one imagine that odours are diffused, like light or like heat and cold, without communication of substance; since he may observe that odours adhere even to solid bodies, as woods and metals, and that for no short time; also that by rubbing and washing they may be dispersed again and cleared away. But in these and similar things, no man in his senses will assert that the process is infinite, seeing this distribution or diffusion is confined to certain spaces, limits, and quantities of bodies; as is most manifestly shown in the above examples. With respect to the second sense of the word atom, namely, that it presupposes a vacuum, and defines an atom as that which is without a vacuum, it was a good and earnest diligence on the part of Hero to deny the existence of a collected vacuum, but maintain that of a vacuum interspersed. For when he saw the constant connection of bodies, and that no space at all could be found or assigned where a body was not; and much more, when he observed that heavy and ponderous bodies are carried upwards, and throw aside and violate their natures, rather than suffer an absolute separation from the body contiguous to them, he laid it down as certain that Nature abhorred any large or collected vacuum. On the other hand, when he perceived that the same matter of a body was contracted and condensed, and again expanded and dilated, and that it occupied and filed unequal spaces, sometimes larger and sometimes smaller, he did not see how this ingress and egress of bodies in their own places could happen except by means of a vacuum interspersed; less when the body was compressed, and more when it was relaxed. For this contraction must needs happen in one of these three ways; either in that just mentioned, namely, by the exclusion of vacuum in proportion to the contraction; or by the forcing out of some other body previously intermixed; or by some natural (whatever that may be) condensation and rarefaction of bodies. Now with regard to the forcing out of a finer body, that process seems to have no end. It is true indeed that sponges and the like porous bodies are contracted when the air is squeezed out; but it is shown by many experiments that the air itself admits of a considerable contraction. Are we then to suppose that the finer part of the air is squeezed out, and out of that part another, and so on for ever? Such an opinion is strongly opposed by the fact that the finer bodies are,

the greater is the contraction they admit of; whereas it should be the contrary, if contraction proceeded from the forcing out of the finer part. And with regard to the other way, namely, that the same bodies, not otherwise changed,.do yet admit of more or less in density or rarity, it need not be much laboured. For it seems to be something positive, depending on a supposition incapable of further explanation, as Aristotle's assertions generally do. There remains therefore the third way, which supposes a vacuum. And if a man object to this, that it appears strange and almost incredible there should be a vacuum interspersed when a body is found everywhere, he will, if he calmly consider the examples adduced above of water coloured with saffron or air infected with odours, easily see that there can be no part of the water specified where saffron is not; and yet it is plain, by comparing the water and saffron together before they are mixed, that the body of the water is immeasurably greater than that of the saffron. And if this be found in the case of different bodies, much more must it be supposed to take place in body and vacuity. But in one respect the conjecture of Hero, a mechanical man, was inferior to that of Democritus, who was a distinguished philosopher; for Hero, because he did not find a collected vacuum in our globe, simply denied its existence; whereas there is no reason why in the regions of the air, where there are doubtless greater expansions of bodies, there may not be also a collected vacuum. But in these and similar inquiries men should be once for all admonished, not to be confounded and distrustful in consequence of the exceeding subtlety of nature, but to think that both the units and the sums of things are equally subject to calculation. For it is as easy to talk or think of 1000 years as of 1000 seconds, although years consist of many seconds. Again, let no one think that this is rather a matter of curious speculation than for work and use. For we may see that almost all philosophers and others who have worked diligently in experience and particulars, and cut nature as it were to the quick, are drawn into these inquiries, though they do not complete them with felicity. And there is no stronger or truer reason why the philosophy we have is barren of effects than this, that it has caught at the subtleties of common words and notions, and has not attempted to pursue or investigate the subtlety of nature.

II.

On the Equality and Inequality of Atoms or Seeds.

The inventions and opinions of Pythagoras were mostly of such a nature as were rather suited to found an order in religion than to open a school in philosophy; and this has been confirmed by the issue. For his discipline has prevailed and flourished more in the heresy of the Manichees and the superstition of Mahomet than with philosophers. Yet his opinion that the world consists of numbers may be so understood as to penetrate to the principles of nature. For there are two opinions, nor can there be more, with respect to atoms or the seeds of things; the one that of Democritus, which attributed to atoms inequality and configuration, and by configuration position; the other perhaps that of Pythagoras, which asserted that they were altogether equal and similar. For he who assigns equality to atoms necessarily places all things in numbers; but he who allows other attributes has the benefit of the primitive natures of separate atoms, besides the numbers or proportions of their conjunctions. Now the practical question which corresponds to this speculative question, and may determine it, is that which was also adduced by Democritus; namely, whether all things may be made out of all things'; and as he believed this to be contrary to reason, he maintained the diversity of atoms. But to me this question does not appear to be well proposed, nor to press the former question, if it be understood of the immediate transmutation of bodies. But the proper question is whether all bodies do not likewise pass through regular circuits and intermediate changes. For there is no doubt but that the seeds of things, though equal, as soon as they have thrown themselves into certain groups and knots, completely assume the nature of dissimilar bodies, till those groups or knots are dissolved; so that the nature and affections of compound bodies may be as great a hindrance and obstacle to immediate transmutation as those of simple. But Democritus, acute as he is in investigating the principles of bodies, when he comes to examine the principles of motions appears to be unequal to himself, and to be unskilful; which

1 Lucretius, i. 784.

likewise was the common fault of all the philosophers. And I know not whether this inquiry I speak of concerning the first condition of seeds or atoms be not the most useful of all; as being the supreme rule of act and power, and the true moderator of hope and works. There is likewise another inquiry flowing from this, which has a less extensive sphere of usefulness, but approaches nearer to things and works. I mean the inquiry concerning separation and alteration; namely, what is done by separation, and what by other means. For it is an error familiar to the mind of man, which has likewise received great strength and increase from the philosophy of the chemists, to impute things to separation, which are due to something else. For instance, when water passes into vapour, one may easily imagine that the finer part of the water is emitted, and the grosser remains; as we may see in wood, where part escapes in flame and smoke, and part remains behind in ashes. And one may suspect that something of the same kind takes place in water, though not so manifestly. For although the whole body of water sometimes appears to bubble up and evaporate, yet some dregs like ashes may adhere to the vessel. But this consideration is deceptive. For it is most certain that the whole body of water may be changed into air, and if anything do adhere to the vessel, this may not happen from the selection and separation of the grosser part; but perhaps because some part (although of a perfectly similar substance to that which escapes) has from its position touched the vessel. And this is very apparent in quicksilver, which becomes totally volatile, and recovers its former consistency without even the slightest loss. Likewise in the oil of lamps and the tallow of candles the whole of the fat becomes volatile without depositing any ashes; for soot is generated after and not before flame, and is the carcass of the flame, not the sediment of the oil or tallow. And this prepares a way to the overthrow of the theory of Democritus on the diversity of seeds or atoms; a way, I mean, in nature; for in opinion the way is much more easy and inviting, because the common philosophy makes its feigned matter indifferent and agreeable to all forms.