In this sequence three particular epochs stand out as fertile in science and favourable to progress--the Greek, the Roman, and our own--"and scarcely two centuries can with justice be assigned to each." The other periods of time are deserts, so far as philosophy and science are concerned.

Rome and Greece are "two exemplar States of the world for arms, learning, moral virtue, policy, and laws." But even in those two great epochs little progress was made in natural philosophy.

For in Greece moral and political speculation absorbed men's minds; in Rome, meditation and labour were wasted on moral philosophy, and the greatest intellects were devoted to civil affairs.

Afterwards, in the third period, the study of theology was the chief occupation of the Western European nations.

It was actually in the earliest period that the most useful discoveries for the comfort of human life were made, "so that, to say the truth, when contemplation and doctrinal science began, the discovery of useful works ceased." So much for the past history of mankind, during which many things conspired to make progress in the subjugation of nature slow, fitful, and fortuitous.