fnfcej. 243 



Grier, John A., quoted, 67. 



Guyot of Provence mentions mariner's compass, 

 21. 



Halske, double transmission, 114. 

 Harmonic telegraphy, 120. 



receivers. \-2~>. 



relay, 130. 



Hawksbee, Francis, electrician, 7. 

 Heat, a mode of motion, 40. 



related to atoms, 42. 



begins and ends in matter, 44. 



electrical and mechanical energy the same. 



46. 

 Henry, Joseph, first practical telegrapher, 90. 



constructs long-distance line, 94. 



produces induction, 177. 

 Heraclea and the loadstone, 20. 

 Hertz experiments in ether-waves, 178. 

 Homer refers to loadstone, 20. 

 Horse-power, 214. 



House, Royal E., printing telegraph, 108, 110. 

 Hughes. David E., printing telegraph, 108, 112. 



Induction, 56. 



guarded against, 169. 

 produced by Henry, 177. 



Keeper of a magnet. 31. 



Kelvin. Lord (Sir \V. Thompson), cable message 



iver. 158. 



" Kirk." in 1,1,-iaphy, 115, 118. 

 Kl. i>t and the Ley den jar, 8. 



her In,//. 

 Leydori jar invented, 8. 



, lectricity; Franklin. 8. 

 restoration of equilibrium. 1 



