La macchina a vapore spiegata e illustrata

Le prime righe

VIADUCT, NEAR WATFORD, BIRMINGHAM RAIL-ROAD. THE STEAM ENGINE. HERO OF ALEXANDRIA. CHAPTER I. [Pg003] TOC INX THE STEAM ENGINE, A SUBJECT OF POPULAR INTEREST.—THE OBJECT OF THIS WORK.—DISPUTES RESPECTING THE INVENTION.—HERO.—DE GARAY.—DE CAUS.—BRANCA.—MARQUIS OF WORCESTER.—PHYSICAL PRINCIPLES.—ELASTIC AND INELASTIC FLUIDS.—THEIR PROPERTIES.—APPLICATION OF THESE PRINCIPLES TO THE ENGINES OF HERO, DE CAUS, AND LORD WORCESTER.—SIR SAMUEL MORLAND.—PAPIN.—ATMOSPHERIC PRESSURE.—THE WEIGHT OF AIR.—LESS AT GREATER HEIGHTS.—BAROMETER.—PRESSURE OF AIR.—ELASTIC FORCE OF AIR AND GASES.—FORCE PRODUCED BY A VACUUM.—COMMON PUMP.—RAREFACTION BY HEAT.—PAPIN'S METHODS OF PRODUCING A VACUUM.—HIS DISCOVERY OF THE CONDENSATION OF STEAM.—SAVERY. (1.) That the history of the invention of a piece of mechanism, and the description of its structure, operation, and [Pg004] uses, should be capable of being rendered the subject matter of a volume, destined not alone for the instruction of engineers or machinists, but for the information and amusement of the public in general, is a statement which at no very remote period would have been deemed extravagant and incredible. Advanced as we are in the art of rendering knowledge popular, and cultivated as the public taste is in the appreciation of the expedients by which science ministers to the uses of life, there is still perhaps but one machine of which such a proposition can be truly predicated: it is needless to say that that machine is the STEAM ENGINE. There are many circumstances attending this extraordinary piece of mechanism which impart to it an interest so universally felt. Whether we regard the details of its structure and operation, the physical principles which it calls into play, and the beautiful contrivances by which these physical