latent, and thus capable of conversion and combinations. Time, he adds, does not exist by itself, but from things that happen sense apprehends the past, the present, and the future.

His second problem is how the universe came into existence, and he argues that it was formed by the collision and cohesion of atoms, as they were continually falling, like flakes of snow, through infinite space; some, as they bounded off from each other, producing air and sunlight, and others stone or iron, according to their varying shapes and tenacities. The same movement which was the beginning of things will continue, he says, for ever. Every object about us is in constant motion, though we do not perceive it, just as a flock of sheep at a distance looks like a stationary speck, or two contending armies seem to be only a glitter of reflected light. Glancing at the theory of a centre of gravity, he dismisses it on the ground that space being infinite, can have no centre, and would yield to heavy bodies if it had. Atoms, he decides, are infinite in quantity, but of limited shapes, and without colour, which is produced by light, and not inherent in anything. are also without sensation, which is the result of complex combinations. The evolution of the universe from atoms, he believed, occupied a very long time, and his sketch of the successive formation of the heavens and the earth corresponds in many respects with that in the book of Genesis. He conceived the number of worlds to be infinite, and endeavoured to measure the sizes of the heavenly bodies by comparison. Night, he imagined, was caused by the sun blowing out his fires, and morning by the seeds of heat streaming together again at a fixed time, just as trees blossom, and boys change their teeth, at regular periods. The variety of substances into which atoms have combined is due, he explains, to their different shapes and sizes, since nothing consists of one kind only of first beginnings, and whatever exists is the result of combinations.

They

Thus he accounts for all the facts of nature, everything being regulated by the form and substance of the atoms composing it, and his great active principle is perpetual

motion, by which the heavens are sustained from falling on the earth, and the void between them is filled with air, whilst minute particles are continuously evaporating from every existing form, and entering into fresh divergences, owing to the unlike forms and textures of things.

Concerning life and consciousness, his idea was that whatever things have sense are all composed of senseless first beginnings. For instance worms spring out of decayed matter; rivers and pastures produce cattle; they form the substance of our bodies, which, in their turn, are often converted into the flesh of wild beasts and vultures. Lite, he argued, is merely a mode of matter, the earth, in the first instance, giving forth the germs from which the vegetable, and afterwards the animal and human forms were developed, and nourished with a liquid like milk exuding from its pores. Many of the forms of animal life, however, were imperfect, and those that were unable to detend themselves forthwith perished in the struggle for existence; but all living things go on after their own fashion, and preserve their distinctive differences, according to a fixed law of nature.

He believed that the vital principle consisted of a subtle ether, composed of exceedingly small atoms of spirit, heat, and air, and something else, still finer, which produced sensation and thought. These four elements, he held, formed the mind and soul which make up a single nature, the mind being the directing principle, and having its seat in the heart, whilst the soul was disseminated through the body, and acted in unison with, but subordinate to, the mind.

Taste, smell, and sound, according to his theory, are touches, more or less violent, of particles of matter, driven against and penetrating our bodies; and, in the same way, Vision is the result of films or pictures perpetually proceeding from every existing object, and bursting against the eyes. The perception of distance, he explains, is not an act of sight, but of inference from the force with which the air that the film drives before it brushes the eyes; and reflection is caused by the action of airs of different volume. Thus, by means of several mirrors, the images of objects may be

transmitted through winding passages, the left side becoming the right, because the film rebounds and strikes backwards. In the case of optical illusions it is not, he says, that our eyes cheat us, but that the mind draws wrong inferences from the images presented to it.

Closely connected with his idea of sight is that of the imagination. Besides the floating films that take possession of the eyes, he conceived the air to be full of others, of a thinner texture, which act upon the mind in combination with those that impress the vision. During sleep, however, when the eyes are insensible to the thicker images, the mind is influenced by the others only, which form all sorts of fantastic entanglements, and hence the explanation of dreams. But, when we are awake, the mind possesses the power of being influenced by images of a certain kind, to the exclusion of others, and, consequently, as the will prompts so the mind thinks, although he does not show how it is that the will is self-determining.

Having thus established the connection between the mind and body, he deduces further that the vital principle cannot exist independently of the body, and that they perish and are dissolved together, just as water is spilt when the vessel containing it is broken. For, he says, if the soul be immortal, and can feel when separated from the body, it must be provided with the five senses, which cannot exist without a body. It is evident, also, from the quivering of a limb after it has been severed from the trunk, that it retains a portion of the vital principle, and, if the soul is capable of being thus divided, how can it be immortal? Again, if it did not die with the body, it would not be dispersed all through it, but set apart by itself. From many similar analogies he draws his final conclusion that the nature of mind cannot come into being alone without a body, nor exist far away from sinews and blood.

He next proceeds to argue that the defects of the world and its occupants make it clear that it cannot be the work of a divine creator, and that as it evidently had a beginning, so will it also have an end, the four elements of which it is composed-fire, water, earth, and air-being in a constant state of transition, and the entire universe a mere bubble,

among a countless number of similar worlds, which are continually falling downwards through an infinite void.

In his summary of human progress, he says that at first men hardly differed from the lower animals, and had neither clothing, shelter, laws, nor religion, the struggle for food, and to protect themselves from wild beasts, occupying all their thoughts. Gradually they learnt to produce fire by rubbing sticks together, and to cast molten metals into various shapes; also to slay animals, and use their skins for clothing, and to build huts. Then followed marriage and family affections. Mutual acts of forbearance were also practised, and men of superior intellect began to influence and rule their fellows; the value of gold, silver, and iron became known, and weaving and other useful arts were invented. In the course of time, kings began to build cities, and to divide the lands and cattle in proportion to men's personal beauty and intelligence; riches were amassed by a few, and became more powerful than virtue or intellect. Language shaped itself slowly, and use impelled men to vary the sounds of the tongue, just as dogs and other creatures utter distinct cries when angry, or when feeding their young, or to give warning of danger; whilst they learnt music from the birds, and from the whistling of the wind through hollow reeds.

Anticipating and refuting the modern theory that religion had its origin in men's wonder at the phenomena of nature, Lucretius conceived it to be the result of deliberate reflection, which attributed them to the existence of gods. They were also impressed, he believed, with the effect of waking and dreaming thoughts on their imaginations, which suggested the more glorious forms and enduring powers of superior beings, dwelling in the spaces between the innumerable worlds or universes, and yet exercising no care or influence over them.

Some extracts from the Poem are appended to illustrate his mode of handling the subject, and his ideas of life and human nature generally.

Speaking of everything reverting to its original atoms, he says,―

'Things seem to die but die not. The spring showers
Die on the bosom of the motherly earth,

Again,

But rise again in fruits and leaves and flowers,
And every death is but another birth.'

Mallock.

'That is a property which cannot be
Disjoined from a thing, and separate,
Without the said thing's death. Fluidity
Is thus a property of water; weight
Is of a stone. Whilst riches, poverty,
Slavery, freedom, concord, war, and hate,
Which change, and not inhere in things of sense,
We name not properties, but accidents.'

The infinity of space he describes thus,—

'Such is the nature, then, of empty space
The void above, beneath us, and around,
That not the thunderbolt, with pauseless pace,
Hurtling for ever through the unplumbed profound
Of time, would find an ending to its race,
Or e'er grown nearer to the boundless bound,
So huge a room around, beneath, above,
Yawns, in which all things being are and move.'

And the formation of the universe as follows,—

'For blindly, blindly, and without design,
Did these first atoms their first meetings try;
No ordering thought was there, no will divine
To guide them; but through infinite time gone by,
Tossed and tormented, they essayed to join,

And clashed through the void space tempestuously
Until at last that certain whirl began,

Which slowly formed the earth, and heaven, and man.

Thus from the depths of all eternity

The unwearying atoms wage a dubious war ;
And now with surging life doth victory lie,
And now anon is death the conqueror.'

To prove that colour cannot exist without light, he says,—

'After this fashion does the ringdove's down

Change in the sun, and shift its plumy sheen
Now all a poppy's dark vermilion,

Now coral, glimmering over emerald green.