CH. ix SCIENTIFIC MOTIVE 235 



to themselves and others. Both these classes of pioneers 

 have their proper places in the scheme of progress, but 

 they live in different atmospheres. The scientific 

 investigator must have freedom to follow his own 

 course wherever it may lead, whereas technical research 

 can be organised and definite problems presented for 

 which solutions of direct service to man are sought. 

 The standard of value in one case is that of knowledge 

 only, while in the other it is that of profit or use. The 

 scientific mind seeks to understand Nature ; the engi- 

 neering mind to control her for material purposes. 



Some time ago the votes of the readers of an American 

 periodical Popular Mechanics were taken as to what 

 inventions were considered to be the " seven wonders 

 of the modern world." From a list of numerous inven- 

 tions, seven had to be selected ; and those which received 

 the highest number of votes were : wireless telegraphy, 

 the telephone, the aeroplane, radium, antiseptics and 

 antitoxins, spectrum analysis, and X-rays. Each one 

 of these things had its foundations in purely scientific 

 work and was not the result of deliberate intention to 

 make something of service to humanity. 



Wireless telegraphy has its origin in the work of Clerk 

 Maxwell and Hertz ; the telephone depends upon the 

 principles of magneto- electric induction discovered by 

 Faraday ; Langley's investigations of the resistance of 

 the air to moving bodies led him to construct the first 

 working model of an aeroplane ; radium was isolated 

 by the Curies solely on account of its scientific interest 

 and without any view of its practical value ; Chloroform 

 was discovered by Liebig and Soubeiran ; nitrous oxide 

 or " laughing gas " by Davy, and sulphuric ether by 

 Valerius Cordus ; the principle of antitoxin treatment 

 was established by Pasteur, Roux and Yersin, and the 



