410

Raising Hot Water by Steam, from Decaus. [Book IV.

are sufficient to prove that the irresistible force of steam when confmed, wasknown in the middle of the sixteenth Century—in fact it always has beenknown since distillation was practised or an eolipile used. Particularcare was always required to keep the orifice of the latter instrument openwhen on the fire.

Besides the Natural Magic of Porta and the writings of Cardan, therewere other Works published in the sixteenth Century in which steam iseither incidentally mentioned, or expressly treated on. About tbe year1560, Mathesius, a G-erman preacher, in Order to illustrate the enormousforce of a little imprisoned vapor, introduced into a sermon a descriptionof an apparatus “ answering to a steam engine”—an instance of ingenuityequal to that of Cardan, who contrived to swell the contents of a treatiseon arithmetic, (which he wrote for the booksellers by the page) by ex-patiating on the motions of the planets, on the Creation, and the tower ofBabel. Canini, a Venetian, made experiments on steam in 1566. In1569, an anonymous tract, printed at Orleans, and ascribed to Besson,contains an account of tbe expansion of water into steam, and the relativevolumes of each. About 1597, a German writer proposed the whirlingeolipile of Heron, as a Substitute for dogs in turning the spit, and recom-mended it in a passage, an extract from which may be seen at page 76 ofthis volume.

The “ Forcible Movements” of Decaus, or de Caus, is the next au-thority for early notices of steam. This work was first published atFrankfort in 1615, and in Paris in 1624. It is entitled Les Raisons desForces Mouvantes, avec diverses machines tant utiles que plaisantes, &c:—Reasons of moving forces, with various machines both useful and inter-esting. The title seems to have been slightly changed in different editions;and, as noticed at page 319, the name of the author also; a circumstance

that has led Mr. Farey to suppose therewere two books, written by different au-thors of the same name. In the English translation of 1659, which consists of twoparts : “ The theorie of the conduct of wa-ter” and the “Forcible movements,” thetheorems on steam are omitted. By thesetheorems Decaus intended to show thatheat carries off water by evaporation—thatsteam when Condensed returns to its origin-al bulk—and that a hollow ball or eolipilemay be exploded by it. The only devicefor employing this fluid which he has given,is in illustration of the fifth theorem, viz:Water maybe raised above its level by meansoffire, : “ The third method of raising wateris by the aid of fire, whereby diverse ma-chines may be made. I shall here givethe description of one. Take a ball ofcopper marked A, well soldered at everypart. It must have a vent hole marked Dby which water may be introduced ; andalso a tube marked C, soldered into theNo. 188. Decaus, A.D. 1615. top of the ball, and the end C reaching

nearly to the bottom, but not touching it.After filling this ball with water through the vent hole, stop it close and