44 PROFESSOR HENRY AND THE 



telegraph, or the still more marvelous telephone. 

 They are to-day essentials of modern living ; and 

 are as familiar to us as spools of cotton. Judg- 

 ing by their results, they constitute the most im- 

 portant discovery which has ever been made in 

 electricity since Volta created the battery. 



Henry also put in operation at Princeton in 1835 

 the very simple and obvious plan of using the "in- 

 " tensity spool and battery," working through long 

 distances, to open and close the circuit of a "quan- 

 " tity spool and battery," stationed where the work 

 was to be done; thus making the powerful mag- 

 net, at short range, the servant of the weak one at 

 long range. In this state he left the problem 

 entirely solved, to those who could procure the 

 money to practically apply his discoveries to the 

 commercial uses of man. 



That task was no easy one. In 1831 there were 

 no railroads and no steamships. Over rough 

 country roads the mails were carried in wagons or 

 coaches, and the postage on a single letter was a 

 shilling for short distances, and twice as much for 

 longer. But little capital had accumulated in this 

 country; and corporations, those powerful instru- 

 ments for uniting the slender means of the many 

 into a compact force for the development of great 

 industrial enterprises, were hardly known. If the 

 most perfect telegraph apparatus of to-day had 

 been then presented to the public, no company 



