by M. de Navarrete, in the form of a letter from Tomás Gonzales, Director of the Royal Archives at Simancas, Spain.
9. In 1601 Giovanni Battista della Porta, in his work "Spiritali," described an apparatus by which the pressure of steam might be made to raise a column of water, and the method of operation included the application of the condensation of steam to the production of a vacuum into which the water would flow. He used a separate boiler. Fig. 3 is copied from an illustration in a later edition of his work.
10. In 1615 Salmon de Caus, who had been an engineer and architect under Louis XIII. of France, and later in the employ of the British Prince of Wales, published a work at Frankfort, entitled "Les Raisons des Forces Mouvantes avec diverses machines tant utile que plaisantes," in which he illustrated his proposition, "Water will, by the aid of fire, mount higher than its level," by describing a machine designed to raise water by the expanding power of steam. (See Fig. 4.)
This consisted of a metal vessel partly filled with water, and in which a pipe was fitted leading nearly to the bottom and open at the top.
Fire being applied, the steam, formed by its elastic force, drove the water out through the vertical pipe, raising it to a height depending upon either the wish of the builder or the strength of the vessel.11. In 1629 Giovanni Branca, of Lovetto, an Italian town, de-
- "I Tre Libri Spiritali," Napoli, 1606.