544 Reviews. [July, 



The first application of steam as a motive power is mentioned by 

 Hero of Alexandria, in his " Uysvjj.arMx." A hollow sphere of metal, 

 capable of free revolution, is furnished with two tubes, which issue 

 from opposite points of its circumference, and are bent near their free 

 extremity at a right angle ; the sphere is partially filled with water, 

 and heated ; the steam issuing from the extremity of the tubes causes 

 the sphere to revolve, on the principle of Barker's mill. Small work- 

 ing models of Hero's engine are to be seen in the windows of instru- 

 ment makers ; and an engine of this form has been patented, and is 

 occasionally used, in the present day. From the time of Hero we 

 hear nothing more of the application of steam till the beginning of the 

 seventeenth century. In a work published about 1600, Hero's engine 

 is recommended to be used for turning spits, its great advantage being 

 that the partakers of the roasted meat may feel confident " 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." 



Hero mentions several devices for producing a fountain by means 

 of compressed air. The apparatus he describes is exactly similar in 

 construction to the compressed air fountain of the present day : a 

 metallic vessel is provided with a tube, which reaches nearly to the 

 bottom of it, and is terminated above by a jet capable of being opened 

 or closed at pleasure. The vessel is partially filled with water, air is 

 then condensed into it by a syringe; on opening the jet, water is 

 forcibly ejected by the condensed air. In 1615, Solomon de Caus, a 

 French engineer, describes and figures a fountain similar in form to 

 that of Hero, but worked by steam instead of by condensed air. 

 He writes as follows : — " Le troisieme moyen de faire monter est par 

 l'aide du feu, dont il se peut faire diverses machines ; j'en donneray 

 ici la demonstration d'une ; " from which it would appear that this 

 was not the first application of steam to the raising of water, although 

 it is always quoted as such. We conceive that but little merit is due 

 to De Caus, if indeed he devised this slight modification of Hero's 

 fountain, which we think improbable. From the time of Hero (and 

 probably long before), a jet of steam was employed in the place of 

 ordinary bellows for blowing fires, water-air could, therefore, take the 

 place of other air (indeed, it was generally believed that all airs were 

 the same), what, then, could be simpler than to extend that replace- 

 ment in other directions ? 



In 1628, Giovanni Branca, an Italian mathematician, produced 

 rotatory motion by causing a jet of steam to impinge against the 

 vanes of a wheel ; the amount of motive power must have been very 

 small. 



We believe John Eey, a physician of Bugue, was the first to raise 

 a piston by steam; in a work published in 1630, he describes a 

 method for determining the volume of air produced from a known 

 volume of water ; for this purpose, he procured a hollow metallic 

 cylinder, open at one end, and closed at the other, with the exception 

 of an orifice, into which the beak of a small elopile covdd be fitted 

 air-tight ; a piston was forced down to the bottom of the cylinder, the 

 elopile, full of water, was then fitted into its place, the water within 



