history of speculation, his speculative writings have been seldom and superficially studied. Besides the materials collected in former editions, Professor Erdmann has enriched his republication with no fewer than twenty-three original documents of Leibnitz, not before published, and which this able and industrious editor has recovered, during an active search in 1836, among the accumulation of manuscripts in the Royal Library of Hanover. Most of these added works relate to that theme, on the subject of which we have already alluded to as the central one of the intellectual life of Leibnitz. It increases the convenience of this edition, that the several works which it includes, 101 in number, have been arranged, as nearly as possible, in the order in which they were written. In this extensive collection, we are glad to recognise the Nouveaux Essais and the Théodicée.
It is not easy to give even a brief exposition of the very miscellaneous contents of these works. The system and manner of thinking of Leibnitz, is to be gathered from his philosophical works studied collectively, rather than from any separate publication. These collected writings bear throughout one very marked characteristic of inventive genius; for they are crowded with richly suggestive germs of thought, cast forth often in disorder, as it were with intent to exercise the generalizing powers of others. From out of this stimulating variety, there may, however, be extracted two or three more prominent ideas, united, as far as possible, by demonstration, with his assumed first principles; for the main purpose of
