A careful perusal of the “Century” will satisfy the reader that its contents relate principally to the practical and useful, notwithstanding that some appear of doubtful value, and some even paradoxical. The variety of cannon and musquetry is singular, the improvements in ships and fortifications quite surprising, and in various mechanical appliances remarkably ingenious. But, after all, what was the special design of its author; what was he principally seeking to establish through this wide course of investigation? It is evident he sought some mechanical power to supersede ordinary wind, water, and animal power. He tried weights and springs, screws and levers, and finally he filled a piece of a cannon three-quarters full of water, which, after making a fire under it, “burst and made a great crack.” The aim and object of all his laborious experiments was now attained, and from the day when he thus burst the cannon, steam power was realized, its application pursued, various kinds of machines constructed, and the strangeness, novelty, and power of the new engine were such that he declared, as in an ecstacy of delight, “I call this _A Semi-omnipotent Engine_, and do intend that a model thereof be buried with me.” Nay, more, he bowed down in adoration before his Maker, rendering him most humble thanks for vouchsafing him “an insight in so great a secret of nature.” It is worth remarking, that the very form of the “Century” was rather due to a custom among scientific inventors than to any whim on the part of its author. In the 13th century, Wilars de Honecort had given a statement of fourteen inventions. In like manner Leonardo da Vinci, of ten various schemes for bridges, ditches, fortifications, and others, military and naval. So again Ralph Rabbards in 1574, Edmund Jentill in 1594, and Henry Marshall in 1595, gave notices of their several discoveries in medical waters, fire-works, and mechanical devices. In 1583, appears a MS. note of twenty “sundry sorts of engynes.” In 1596, Lord Napier wrote concerning his four “secret inventions,” concluding:--“These inventions, besides devices of sailing under water, with divers other devices and stratagems for harming of the enemies, by the grace of God, and work of expert craftsmen, I hope to perform.” In James the First’s reign was published a tract entitled, “Cornu-Copia: a miscellaneum of lucriferous and most fructiferous experiments, observations, and discoveries, immethodically distributed; to be really demonstrated and communicated in all sincerity.” The suggestions, amounting to seventeen, are chemical, medicinal, agricultural, and mechanical. In 1632, Thomas Grent patented six inventions, not one of which is otherwise described than after this manner:--“First. An instrument very profitable when common windes doe fail, for a more speedy passage of calmed shipps, or other vessels upon the sea or great rivers, which may be called the wind’s mate.” In 1636, Sir John C. Van