158 BIOGExiPIIICAL MEMOIR OF JOSEPH HEXEY. 



narrative proceeded. But one trait ma^^ not be wholly omitted from the 

 biography of one who has well been called " the model of a Christian 

 gentleman," and who is also our best example of a physical philosopher. 

 His life was the practical harmony of the two characters. His entire 

 freedom from the doubts which disturb some minds is shown in that 

 last letter which he dictated, in which he touches the grounds of 

 faith both in natural and revealed religion; also in his sententious 

 declaration upon some earlier occasion, that the person who thought 

 there could be any real conflict between science and religion must be 

 either very young in science or ignorant of religion. 



The man for whom this memorial is placed was a veteran in both ; was 

 one of that noble line of natural philosophers for whom we may in all 

 sincerity render to Almighty God hearty thanks, not only for the good 

 example and fruit of their lives, but also that, having finished their 

 course in faith, they do now rest from their labors. 



SUPPLEMENTARY NOTES. 



XOTE I. 



SEQUENCE OF DISCOVEEY AND INVEXTIOX RESULTING IN THE ELEC- 

 TRO-MAGNETIC TELEGRAPH. 



The following appear to be the main points in the order of discovery 

 which led to the electro-magnetic telegraph. They are here condensed 

 from Professor Henry's "Statement", in the "Proceedings of the Re- 

 gents", published in the Sraitlisonian Eeport for the year 1857, and from 

 a note appended by Mr. William B. Taylor to his "Memoir of Joseph 

 Henry and his Scientific Work," read before the Philosophical Society of 

 Washington. 



1810-1820. Oersted showed that a magnetic needle is deflected by the 

 action of a current of galvanic electricity passing near it. It 

 appears that this discovery had already been made as early as 

 the year 1802, by Romagnesi, and published in 180o. 

 1820. Arago discovered that while a galvanic current is passing through 

 a copper wire it is cai)able of developing magnetism in soft 

 iron. 

 1820. Ampere discovered that two wires through which currents are 

 passing in the same direction attract, and in opposite directions 

 repel, each other ; and thence he niferred that magnetism con- 

 sists in the attraction of electrical currents revolving at right 

 angles to the line joining the two poles of "the magnet, and 

 is produced in a bar of steel or iron by induction from a series 

 of electrical currents revolving in the same direction at right 

 angles to the axis of the bar. 

 1820. Schweigger in the same year jiroduced the galvanometer. 

 1825. Sturgeon made the electromagnet by bending the bar, or rather 

 a piece of iron wire, into the form of a horse-shoe, covering it 



