The _Advancement_, in part at least, was probably a hurried work.

It shadowed out, but only shadowed out, the lines of his proposed reform of philosophical thought; it showed his dissatisfaction with much that was held to be sound and complete, and showed the direction of his ideas and hopes.

But it was many years before he took a further step.

Active life intervened.

In 1620, at the height of his prosperity, on the eve of his fall, he published the long meditated _Novum Organum_, the avowed challenge to the old philosophies, the engine and instrument of thought and discovery which was to put to shame and supersede all others, containing, in part at least, the principles of that new method of the use of experience which was to be the key to the interpretation and command of nature, and, together with the method, an elaborate but incomplete exemplification of its leading processes.
Here were summed up, and stated with the most solemn earnestness, the conclusions to which long study and continual familiarity with the matters in question had led him.