He assures Parliament that his several inventions are “practicable with my directions, by the unparalleled workman both for trust and skill, _Caspar Kaltoff’s_ hand, who hath been these five and thirty years as in a school under me employed.” So that, dating from 1663, when he made this statement, we are thus carried back to the year 1628, about the period of his first marriage, and the whole comprises a space of time from the 27th to the 62nd year of his age. How had he employed the peaceable portion of those 35 years? It seems to have been peculiar to the noble experimenter to keep his favourite workman fully employed in putting into practice whatever was known, and in that way establish his own improvements. We can find some analogous device in old scientific writings for the greater part of the subjects he investigated; and it is no disparagement of his ingenuity to say that his refinements may often be traced to the crude efforts made by others to attain similar results. Italy, Germany, Holland, and France abounded in authors whose works we may easily imagine formed a favourite portion of his library; Vitruvius, Vegetius, Hero, Ramelli, Branca, De Caus, Fludd, Besson, Van Etten, Schwenter, Porta, Lana, and other similar tomes replete with engraved brass, copper, and wood-engravings. But the English press likewise produced such works, as Bourne’s Inventions, 1578; Lucar’s Lucar-solace, 1590; Bate’s Mysteries of Art, 1634; Wilkins’ Mathematical Magick; Porta’s Natural Magick, 1658; De Caus’ New and Rare Inventions, 1659, &c. Of all these we are disposed to think that _Bate’s Mysteries of Nature and Art_ was an early favourite; the second edition appeared in 1635, when the Marquis was 34 years of age. The first portion of the work on “Water-works” opens with the observation: “It hath beene an old saying amongst Philosophers, and experience doth prove it to bee true, _Non datur vacuum_, that is to say, Nature will not admit of any vacuity or emptinesse. For some or other of the Elements, but especially Ayre and Water, doe insert themselves into all manner of concavities, or hollownesses, in, or upon the earth, whether they are such as are formed either by Art or Nature.” Through 82 pages the same subject of Water-works is carefully examined, and at page 57, is a description with engravings of “the Watermill or Engine neare the North end of London Bridge.”