22 Professor Tyndall [Jan. 17, 



the carbons as it does to the interior of a flame. The temperature 

 of the flame is lowered by the admixture of a gas which consti- 

 tutes four-fifths of our atmosphere, and which, while it appropriates 

 and diff'uses the heat, does not aid in the combustion. This lower- 

 ing of the temperature by the inert atmospheric nitrogen renders 

 necessary the combustion of a greater amount of gas to produce the 

 necessary light. In fact, though the statement may appear para- 

 doxical, it is entirely because of its enormous actual temperature that 

 the electric light seems so cool. It is this temperature that renders 

 the proj)ortion of luminous to non-luminous heat greater in the 

 electric light than in our brightest flames. The electric light, more- 

 over, requires no air to sustain it. It glows in the most perfect 

 air vacuum. Its light and heat are therefore not purchased at the 

 expense of the vitalizing constituent of the atmosphere. 



Two orders of minds have been implicated in the development of 

 this subject ; first, the investigator and discoverer, whose object is 

 purely scientific, and who cares little for practical ends ; secondly, the 

 practical mechanician, whose object is mainly industrial. It would be 

 easy, and probably in many cases true, to say that the one wants to 

 gain knowledge, while the other wants to make money ; but I am 

 persuaded that the mechanician not unfrequently merges the hope of 

 profit in the love of his work. Members of each of these classes are 

 sometimes scornful towards those of the other. There is, for example, 

 something superb in the disdain with which Cuvier hands over the 

 discoveries of pure science to those who apply them : " Your grand 

 practical achievements are only the easy application of truths not 

 sought with a practical intent — truths which their discoverers pursued 

 for their own sake, impelled solely by an ardour for knowledge. 

 Those who turned them into practice could not have discovered them, 

 while those who discovered them had neither the time nor the inclina- 

 tion to pursue them to a practical result. Your rising workshops, your 

 I^eopled colonies, your vessels which furrow the seas; this abundance, 

 this luxury, this tumult " — " this commotion," he would have added, 

 were he now alive, " regarding the electric light " — " all come from 

 discoverers in Science, though all remain strange to them. The day 

 that a discovery enters the market they abandon it, it concerns them 

 no more." 



In writing thus, Cuvier probably did not sufficiently take into 

 account the reaction of the applications of science uj^on science itself. 

 The improvement of an old instrument or the invention of a new one 

 is often tantamount to an enlargement and refinement of the senses of 

 the scientific investigator. Beyond this, the amelioration of the 

 community is also an object worthy of the best eftbrts of the human 

 brain. Still assuredly it is well and wise for a nation to bear in 

 mind that those practical ajjplications which strike the public eye, 

 and excite public admiration, are the outgrowth of long antecedent 

 labours begun, continued, and ended under the ojieration of a purely 



