CATALOGUE OF THE MECHANICAL ENGINEERING COLLECTION. 



13 



whose efforts to utilize steam to do work, date, it is now believed, 

 from 50 A. D. to 1760 A. D. If the steam engine is considered in its 

 modern sense, however, then Hero's " aeolipile," and the engines 

 made by Papin about 1690 A. D., are the only true ones, for those 

 which followed Hero's and preceded Papin's engines were contri- 

 vances for raising water by steam and had no means of operating 

 machinery directly, although they raised water which in turn oper- 

 ated a water wheel. 



Hero's engine is a true rotary steam engine working on the same 

 principle as that of the turbine. Branca (A. D. 1629) directed 



THE LEFFEL TURBINE. 



steam to strike the vanes of a wheel, causing it to rotate. Dr. Denis 

 Papin, of Blois, France, built a water elevator consisting of two 

 vessels, one in which steam was generated and the other containing 

 the water to be elevated. The former was equipped with a safety 

 valve and the latter contained a float resting on the water and upon 

 which the steam acted, thus decreasing the amount of condensation. 

 This float was the precursor of the piston, invented by Papin. 

 Thomas Savery patented in England a " fire engine " in 1698, which 

 raised water by the direct pressure of steam alternating with atmos- 

 pheric pressure, which proved to be the first practical application 

 of steam power. 



