450 FRAGMENTS OF SCIENCE. 



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 paradoxical, it is entirely 

 because of its enormous actual temperature that the 

 electric light seems so cool. It is this temperature 

 that renders the proportion of luminous to non-luminous 

 heat greater in the electric light than in our brightest 

 flames. The electric light, moreover, 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 vitalising constituent of the atmo- 

 sphere. 



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 

 wishes 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 : c 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 inclination to pursue them to a practical 

 result. Your rising workshops, your peopled colonies, 



