One of De Caus’s expedients for raising water consisted of an apparatus in which he proposed to employ the expansive power of steam for the purpose. In Hero’s book it is shown how a column of water may be thrown up by means of compressed air; and De Caus merely proposed to employ steam instead of air. His apparatus was very simple. It consisted of a spherical vessel fitted with two pipes, one of them provided with a cock and funnel; the other, which reached down to near the bottom of the vessel, being open at the top to the external air. When the vessel was filled with water and a fire lit underneath, the water was forced up the open tube in a jet, greater or less in proportion to the elasticity of the steam. When both tubes were tightly closed, so that neither steam nor water could escape, the heat, says De Caus, would shortly cause a compression from within so violent that “the ball will burst in pieces, with a noise like a petard.” [Illustration: DE CAUS’S STEAM APPARATUS.] It will be observed that there was little mechanical contrivance, and no practical use in this apparatus; it merely furnished an illustration of the extraordinary force of pent-up steam, and that was all. Though De Caus made many experiments with his steam-vessel, he never succeeded in making--if, indeed, he ever attempted to make--a working steam-engine of any kind. It is not improbable that he was dismayed, as others were, by the apparent violence of the imprisoned monster; and it needed a more ingenious head than his to contrive a method of rendering him docile, and making him go quietly in harness.[5]