y 



FIG. 152. BENJAMIN FRANKLIN. 



CHAPTER XIII. 



PHYSICS OF THE EIGHTEENTH CENTURY (continued}. ELECTRICITY. 



IN the history of each science there are periods which have a special 

 lustre from the number and brilliancy of their discoveries. In 

 the present chapter we have to treat of a science which scarcely had 

 an existence at all before the eighteenth century; yet its history from 

 that time to the present day is a voluminous record of the continuous 

 revelation of previously unsuspected and very wonderful truths. The 

 facts which it investigates are in some respects stranger than all the 

 tales of fairyland or the wildest dreams of magic. A very few of the 

 phenomena of Electricity were known before the period we are now 

 considering. The only experimental data were observations of Gilbert 

 of Colchester (page 94), and those of Otto von Guericke, the inventor 



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