To Our Supporters 



When Kdward Livingston Younians founded 

 the Popular Science Monthly in 1 872, he had a very 

 clear purpose in mind. "Science is not the 

 mystery of a class," he put it, "but the com- 

 mon interest of rational human beings." And 

 so he would tell a contributor: "Keep in your 

 mind's eye a person of common intelligence and 

 quite unacquainted with the subject you arc 

 seeking to explain." 



When I assumed the editorship of the Popular 

 Science Monthl\ a year ago, I made up my mind 

 that we must never lose sight of Youman's ideal. 

 The opportunity was rich. Wireless telegraphy, 

 aeroplanes, automobiles, radium, X-Rays, all were 

 unknown in his day. In a single vear more 

 scientific discoveries and important inventions 

 are now made than in a whole decade fort)' years 

 ago. And then, the technique of printing and 

 illustrating has developed mar\'elously. There 

 was no half-tone process when the Popular Science 

 Monthly was founded, no rapid and effective 

 waj' of driving home a point by picture. 



With this wealth of modern material and with 

 wonderful modern facilities, the Popular Science 

 Monthly entered upon a new phase of its career 

 a year ago. In that brief space of time its 

 circulation has more than doubled. Ov^er two 

 hundred thousand copies are now printed. And 

 the circulation is growing by leaps and bounds. 



I wish to thank the man\^ thousands of sup- 

 porters who have made this success possible and, 

 above all, the hundreds of contributors who have 

 helped me to present the facts of current sci- 

 ence, engineering and invention interestingly and 

 truthfully. 



NJeji;^^^ ^^M^^^^ 



641 



