26o PROGRESS OF SCIENCE. 



such a violent electro-atmospheric storm will ensue, that 

 globes from which air has been partially pumped out will 

 glow and throb as if powerful electric currents were directed 

 upon them." These and other unsuspected phenomena were 

 disclosed by Tesla (as recently as February, 1892) which 

 will probably be the starting-point of a new series of 

 discoveries of natural laws and applications, as already 

 hinted in the preceding notice, that will effect changes in 

 humanity even " more general and more wonderful than 

 those brought about by steam and electricity." For, if we 

 once are able to make direct use, as we do in the case of 

 electricity, of the molecular ocean which surrounds us and 

 which "we have let slip through our ringers since the be- 

 ginning of time," we shall then, as M. Tesla put it, "hook 

 our machinery on to the machinery of nature, or harness 

 natural forces to our machinery, and obtain unlimited power, 

 so that manual labour would become unnecessary." 



GROUP VII. INVENTORS. 



To those great men of science we should add a few 

 of the practical men who made important applications of 

 scientific laws, mentioning only those whose inventions 

 have proved to be powerful springs of progress. 



1647 1714. Papin applied to his steam-pump his 

 invention of. the PISTON, the CYLINDER, and the SAFETY 



VALVE (1690). 



17361819. Watt invented the SEPARATE CONDENSER 

 and the DOUBLE-ACTION STEAM-ENGINE the essentials of 

 all steam machinery and made the law of elasticity of gases 

 (explained to him by Black) a new power. 



1765 1815. Fulton, after the STEAMBOATS of Jouffroy 

 D'ALBANS (1783)* and of W. SYMINGTON (1789), arrived at 

 the practical application of STEAM TO NAVIGATION, and 



* Jouffroy d'Albans (1751 1832), whose original drawings can be 

 seen in the South Kensington Museum, built a paddle-steamer which 

 was launched on the I5th of July, 1783, and plied for traffic on the Saone 

 and Rhone for more than a year. Fulton is said to have been a pupil of 

 his, but this is doubtful. 



