Smelting Ore with the blast of an Eolipile.

397

Chap. 3.1

of his Mundus Subterraneus, page 203.) We do not remember to havemet with a figure of an eolipile applied to the fusing of glass or metal,except in the Aula Subterranea of Lazarus Brokers (or Erckern) on Me-tallurgy, published in German, in 1672, and which, like that of Agricola,is illustrated with numerous cuts. The author was Superintendent of themines of Hungary , Germany , and the Tyrol, under three Emperors , andhis work is said to contain every thing necessary to be known in theassaying of metals. The annexed figure is copied from the fifth edition,

(with notes) published at Frankfort onthe Mayn, in 1736. It is named Einetupfferne kugel darinn Wasser ist, wirdubers ffeuer geselct, und an statt Einesblas-balgs gebraacht, and is representedas smelting copper ore in a cupelo fur-nace. Erckers has figured it twice—at pages 1 and 136.

It is not a little singulär that thismode of increasing the intensity offires by ajet of steam directed into theburning fuel has recently been patent-ed both in this country and Europe.It does not however appear to haveanswered the expectations formed ofit, since it has never come into generaluse, nor are we aware that it is at

No 185 . Smaltin? ore with the blast of an present, emploved at all. T wo obvi-

EoUpile. r r . , . ,

ous dtscrepancies between ancient and

modern applications of steam for such purposes may here be noticed, sincethey will, we think, account for the failure of the latter : one is in thenature of the fuel—the other in the temperature of the blast. In the oldeolipiles, the steam, having but a very minute passage thrpugh which toescape, was raised to a temperature which far exceeded that which isgenerated in ordinary steam engine boilers—the vapor was perfectly in-visible, and its escape only known by the sound of the blast, and its effecton the fire. But in late experiments the current consisted of steam loadedwith moisture—a mass of aqueous globules poured into the fire, instead ofthe rarefied and glowing aura that rushed with such impetuous velocityfrom eolipiles. The powerful effect of the latter on fires of wood andcharcoal is unquestionable, but the results of similar blasts on other kindsof fuel (as stone coal) has not yet we believe been sufficiently ascertained.Another difference consisted in the dimensions of the volumes of theblasts :—the one from the eolipile was small and compact—that of theother large and diffuse, a circumstance that may account still further forthe different results; forit should be remembered that in using an eolipileit is not the jet of steam alone that is impelled against the burning fuel,but a volume of atmospheric air is set in motion by the blast and carriedinto the fire along with it : the sarae thing takes place in using a commonbellows, more air being forced against the fire than what issues from thenozzle ; and hence as the velocity of the jet from an eolipile was muchgreater and the jet itself smaller than those of modern applications ofsteam for the same purpose, a much larger proportion of air was alsoborne along with it. It is pro! jble that on particular occasions the an-cients filled them with oil or spirituous liquors instead of water, in Orderto promote a more rapid combustion.

The idea of increasing the heat of fires by water is very old. Pliny