A fire being made beneath the cauldron, steam is formed and finds exit through the pipe, E F G, into the globe, and thence rushes out of the pipes, H K, turning the globe on its axis, G L, by the unbalanced pressure thus produced.
The more elaborate sketch which forms the [frontispiece] represents a machine of similar character. Its design and ornamentation illustrate well the characteristics of ancient art, and the Greek idea of the steam-engine.
This “Æolipile” consisted of a globe, X, suspended between trunnions, O S, through one of which steam enters from the boiler, P, below. The hollow, bent arms, W and Z, cause the vapor to issue in such directions that the reaction produces a rotary movement of the globe, just as the rotation of reaction water-wheels is produced by the outflowing water.
It is quite uncertain whether this machine was ever more than a toy, although it has been supposed by some authorities that it was actually used by the Greek priests for the purpose of producing motion of apparatus in their temples.
It seems sufficiently remarkable that, while the power of steam had been, during all the many centuries that man has existed upon the globe, so universally displayed in so many of the phenomena of natural change, that mankind lived almost up to the Christian era without making it useful in giving motion even to a toy; but it excites still greater surprise that, from the time of Hero, we meet with no good evidence of its application to practical purposes for many hundreds of years.
Here and there in the pages of history, and in special treatises, we find a hint that the knowledge of the force of steam was not lost; but it is not at all to the credit of biographers and of historians, that they have devoted so little time to the task of seeking and recording information relating to the progress of this and other important inventions and improvements in the mechanic arts.
Malmesbury states[7] that, in the year a. d. 1125, there existed at Rheims, in the church of that town, a clock designed or constructed by Gerbert, a professor in the schools there, and an organ blown by air escaping from a vessel in which it was compressed “by heated water.”
Hieronymus Cardan, a wonderful mathematical genius, a most eccentric philosopher, and a distinguished physician, about the middle of the sixteenth century called attention, in his writings, to the power of steam, and to the facility with which a vacuum can be obtained by its condensation. This Cardan was the author of “Cardan’s Formula,” or rule for the solution of cubic equations, and was the inventor of the “smoke-jack.” He has been called a “philosopher, juggler, and madman.” He was certainly a learned mathematician, a skillful physician, and a good mechanic.
Many traces are found, in the history of the sixteenth century, of the existence of some knowledge of the properties of steam, and some anticipation of the advantages to follow its application. Matthesius, a. d. 1571, in one of his sermons describes a contrivance which may be termed a steam-engine, and enlarges on the “tremendous results which may follow the volcanic action of a small quantity of confined vapor;”[8] and another writer applied the steam æolipile of Hero to turn the spit, and thus rivaled and excelled Cardan, who was introducing his “smoke-jack.”
As Stuart says, the inventor enumerated its excellent qualities with great minuteness. He claimed that it would “eat nothing, and giving, withal, an assurance to those partaking of the feast, whose suspicious natures nurse queasy appetites, that the haunch has not been pawed by the turnspit in the absence of the housewife’s eye, for the pleasure of licking his unclean fingers.”[9]