processes and facts of Nature by ordinary observation, without the resources of experiment and of scientific method built upon experiment. The weak points of this philosophy, the mistaken aim and incomplete method of enquiry, the real ignorance of facts disguised under an appearance of systematic treatment, the unproductiveness of the results for any practical accession to man's power over Nature, are quite obvious to any modern reader, who, without any special study of physical science, cannot help being familiar with information which is now universally diffused, but which was beyond the reach of the most ardent enquirers and original thinkers of antiquity. But the amount of information possessed by different ages, or by different men, is no criterion of their relative intellectual power. The mental force of a strong and adventurous thinker may be recognised struggling even through these mists of error. The weakness of the system, interpreted by Lucretius, is the necessary weakness of the childhood of knowledge. But along with the weakness and the ignorance there are also the keen feeling, the clear eye, and the buoyant fancies of early years,--the germs and the promise of a strong maturity. The full light in which ancient poetry, history, and mental philosophy can still be read, makes us apt to forget that a great part even of the intellectual life of antiquity has left scarcely any record of itself. Of one aspect of this intellectual life Lucretius is the most complete exponent. The genius of Plato and Aristotle has been estimated, perhaps, as justly in modern as in ancient times. But the great intellectual life of such men as Democritus, Empedocles, or Anaxagoras, escapes our notice in the more familiar studies of classical literature. The work of Lucretius reminds us of the intensity of thought and feeling, the clearness and minuteness of observation, with which the earliest enquiries into Nature were carried on. In some respects the general ignorance of the times enhances our sense of the greatness of individual philosophers. Each new attempt to understand the world was an original act of creative power. The intellectual strength and enthusiasm displayed by the poet himself may be regarded as some measure of the strength of the masters, who filled his mind with affection and astonishment.