In this Collection of their Discourses, and Treatises, my Reader beholding so many to pass under the name of Hypotheses, may perhaps imagine that this consists not so well with their Method, and with the main purpose of their Studies, which I have often re∣peated to be chiefly bent upon the Operative, rather than the Theoretical Philosophy. But I hope he will be satisfied, if he shall remember, that I have already re∣mov'd this doubt, by affirming, that whatever Prin∣ciples, and Speculations they now raise from things, they do not rely upon them as the absolute end, but only use them as a means of farther Knowledge. This way the most speculative Notions, and Theorems that can be drawn from matter, may conduce to much profit. The light of Science, and Doctrines of cau∣ses, may serve exceeding well to promote our Experi∣menting; but they would rather obscure, than illu∣minate the mind, if we should only make them the perpetual Objects of our Contemplation: as we see the light of the Sun, is most beneficial to direct our footsteps in walking, and our hands in working, which would certainly make us blind, if we should only continue fix'd, and gazing on its Beams.The Histories they have gather'd are either of Na∣ture,§. XXXIX. The Histo∣ries they have collect∣ed.Arts, or Works. These they have begun to col∣lect by the plainest Method, and from the plainest In∣formation. They have fetch'd their Intelligence from the constant and unerring use of experienc'd Men of the most unaffected, and most unartificial kinds of life. They have already perform'd much in this way, and more they can promise the world to accomplish in a very short space of Time.There are already brought in to them the History0