A history of the growth of the steam-engine . orta an improved Heros Fountain, and was named his Steam described with perfect accuracy the action of condensa-tion in producing a vacuum, and sketched an apparatus inwhich the vacuum thus secured was filled by water forcedin by the pressure of the external atmosphere. His con-trivances were not apparently ever applied to any practicallyuseful purpose. We have not yet passed out of the age ofspeculation, and are just approaching the period of applica-tion. Porta is, nevertheless, entitled to credit as having pro- > Pneumaticorum lib
A history of the growth of the steam-engine . orta an improved Heros Fountain, and was named his Steam described with perfect accuracy the action of condensa-tion in producing a vacuum, and sketched an apparatus inwhich the vacuum thus secured was filled by water forcedin by the pressure of the external atmosphere. His con-trivances were not apparently ever applied to any practicallyuseful purpose. We have not yet passed out of the age ofspeculation, and are just approaching the period of applica-tion. Porta is, nevertheless, entitled to credit as having pro- > Pneumaticorum libri tres, etc., 4to. Naples, 1601. I Pre LibriSpiritaU. Napoli, 1606. 14 THE STEAM-ENGINE AS A SIMPLE MACHINE. posed an essential change in this succession, which beginswith Hero, and which did not end with Watt. The use of steam in Pleros fountain was as necessary astep as, although less striking than, any of the subsequentmodifications of the machine. In Portas contrivance, too,we should note particularly the separation of the boiler from. Fi«. 4.—Portas Apparatus, a. c. 1601. the forcing vessel—a plan often claimed as original withlater inventors, and as constituting a fair ground for specialdistinction. The rude engraving (Fig. 4) above is copied from thebook of Porta, and shows plainly the boiler mounted abovea furnace, from the door of which the flame is seen issuing,and above is the tank containing water. The openmg in thetop is closed by the plug, as shown, and the steam issuing THE PERIOD OP SPECULATION. 15 from the boiler into the tank near the top, the water isdriven out through the pipe at the left, leading up from thebottom of the tank. Florence Rivault, a Gentleman of the Bedchamber to
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Keywords: ., bookcentury1800, bookdecade1870, bookidc, booksubjectsteamengines
