Political activity however and Court intrigue left room in his mind for the philosophical speculation which had begun with his earliest years. Amidst debates in Parliament and flatteries in the closet Bacon had been silently framing a new philosophy. It made its first decisive appearance after the final disappointment of his hopes from Elizabeth in the publication of the "Advancement of Learning." The close of this work was, in his own words, "a general and faithful perambulation of learning, with an enquiry what parts thereof lie fresh and waste and not improved and converted by the industry of man; to the end that such a plot, made and recorded to memory, may both minister light to any public designation and also serve to excite voluntary endeavours." It was only by such a survey, he held, that men could be turned from useless studies, or ineffectual means of pursuing more useful ones, and directed to the true end of knowledge as "a rich storehouse for the glory of the Creator and the relief of man's estate." The work was in fact the preface to a series of treatises which were intended to be built up into an "Instauratio Magna," which its author was never destined to complete, and of which the parts that we possess were published in the following reign. The "Cogitata et Visa" was a first sketch of the "Novum Organum," which in its complete form was presented to James in 1621. A year later Bacon produced his "Natural and Experimental History." This, with the "Novum Organum" and the "Advancement of Learning," was all of his projected "Instauratio Magna" which he actually finished; and even of this portion we have only part of the last two divisions. The "Ladder of the Understanding," which was to have followed these and led up from experience to science, the "Anticipations," or provisional hypotheses for the enquiries of the new philosophy, and the closing account of "Science in Practice" were left for posterity to bring to completion. "We may, as we trust," said Bacon, "make no despicable beginnings. The destinies of the human race must complete it, in such a manner perhaps as men looking only at the present world would not readily conceive. For upon this will depend, not only a speculative good, but all the fortunes of mankind, and all their power."