THE ELECTRIC TELEGRAPH. 



PAET I. 



SKETCH OF THE HISTORY AND PROGRESS OF THE ELECTRIC 

 TELEGRAPH, WITH DESCRIPTIONS OF SOME OF THE 

 APPARATUS, 



I. EARLY OBSERVATIONS OF ELECTRICAL PHENOMENA. 



1. THE phenomenon of electrical attraction produced by 

 friction of bodies- was, in some instances, known to the 

 ancients. It was first noticed about six hundred years before 

 the Christian era, by Thales, the founder of Ionic philosophy. 

 He observed that when amber was subjected to friction it 

 acquired the power of attracting light substances, such as 

 bits of feathers. On this account he was led to attribute to 

 amber a species of vitality. The next mention we find is that 

 of Theophrastus, who, three hundred years later, observed 

 that a hard stone (supposed to be tourmaline), when rubbed, 

 attracted straws and little pieces of sticks in its vicinity. 

 Pliny, as well as other naturalists, both Greek and Roman, 

 remarked, at different dates, the same phenomenon, which 

 they regarded, in the spirit of the times, with superstitious 

 reverence. 



2. No systematic inquiry into the subject was undertaken 

 until Dr. Gilbert, towards the close of the sixteenth century, 



