SCIENCE IN THE INDUSTRIAL WORLD 



pulsatory currents produce only sounds differing in 

 intensity; while undulatory currents are those which 

 alternately diminish and increase. These last are the 

 currents essential to the modern telephone, and it was 

 largely upon his knowledge of the nature and action of 

 such currents that Bell based his contention of priority 

 over Gray in his intimate knowledge of the actual work- 

 ings of the telephone. 



It will be recalled that the caveat sent to the patent 

 office by Bell reached there only two hours before a 

 similar caveat sent by Elisha Gray. The patent 

 office, therefore, issued the patent to Bell, although 

 the time between the receipt of the two caveats was so 

 short that common justice would demand that both 

 Bell and Gray be considered as equally entitled to the 

 credit of inventing the telephone, provided both in- 

 struments described were equally practical. Of course 

 in the mere issuance of the patent, Bell was as legally 

 entitled to his claim as if the difference in time of 

 making the application had been days or weeks instead 

 of hours; but Bell contended, probably with good 

 ground for his contention, that Gray did not at the 

 time understand the importance of what are known 

 as the undulatory currents. He did refer to them 

 specifically in his caveat, to be sure, but Bell pointed out 

 that the currents thus referred to were really the pul- 

 satory currents and not the true undulatory ones. 

 This, however, is the theoretical and not the practical 

 side of the question. The demonstration that a speak- 

 ing telephone was a practical possibility was made 

 by Bell and not by Gray, and he must, therefore, go 



