208 FIELDS, FACTORIES AND WORKSHOPS. 



ing and perforating then, and then only, a doctor, 

 Mayer, ventured to bring out the mechanical theory of 

 heat with all its consequences : and yet the men of 

 science almost drove him to madness by obstinately 

 clinging to their mysterious caloric fluid, and they de- 

 scribed Joule's work on the mechanical equivalent of 

 heat as " unscientific ". 



When every engine was illustrating the impossibility 

 of utilising all the heat disengaged by a given amount 

 of burnt fuel, then came the law of Clausius. When all 

 over the world industry already was transforming motion 

 into heat, sound, light, and electricity, and each one into 

 each other, then only came Grove's theory of the " corre- 

 lation of physical forces ". It was not the theory of 

 electricity which gave us the telegraph. When the tele- 

 graph was invented, all we knew about electricity was 

 but a few facts more or less badly arranged in our books ; 

 the theory of electricity is not ready yet; it still waits 

 for its Newton, notwithstanding the brilliant attempts 

 of late years. Even the empirical knowledge of the laws 

 of electrical currents was in its infancy when a few bold 

 men laid a cable at the bottom of the Atlantic Ocean, 

 despite the warnings of the authorised men of science. 



The name of " applied science " is quite misleading, 

 because, in the great majority of cases, invention, far 

 from being an application of science, on the contrary 

 creates a new branch of science. The American bridges 

 were no application of the theory of elasticity ; they 

 came before the theory, and all we can say in favour of 

 science is, that in this special branch, theory and prac- 

 tice developed in a parallel way, helping one another. 

 It was not the theory of the explosives which led to the 

 discovery of gunpowder; gunpowder was in use for 

 centuries before the action of the gases in a gun was 

 submitted to scientific analysis. And so on. The great 

 processes of metallurgy ; the alloys and the properties 

 they acquire from the addition of very small amounts of 



