In the case of Smith vs. 1 )()\vinns, a telegraph infringement suit 



tried at Boston in 1850, a witness, Oliver Byrne by name, made the 



following statement. 



"In the year 1830, I attended the public lectures of Abraham Hooth fafterward 

 scientific reporter for the Times newspaper, and who became Dr. Booth), delivered in 

 Dublin, among other subjects, on electricity and electro-magnetism. In said lec- 

 tures, the said Booth, in my presence, used in combination a long circuit of insulated 

 wire conductors, or galvanic battery, an electro-magnet with an armature and mer- 

 cury cups to join and disjoin the circuit, with which he magnetized and demagnetized 

 the iron of the electro-magnet, causing it to attract the armature when the circuit was 

 joined, and to recede from it when disjoined. Mr. Booth, at that time, stated to his 

 audiences that that power could be produced and used at distant places, as signs of 

 information; and he repeatedly illustrated what he meant, by causing the armature to 

 approach the magnet, and then to fall from it on the floor, stating at the same time 

 that it made marks by so falling." "^ 



A search was made of various indices and publications, including The 



Royal Society Catalogue of Scientific Papers, 1800-1863; Transactions 



of Royal Irish Academy, 1786-1886; Royal Dublin Society Catalogue, 



1731-1839, by J. F. Jones; British Museum Catalogue; Glazebrook's 



Dictionary of Applied Physics; J.J. Fahie's History of the Telegraph, 



previously referred to; and William B. Taylor's An Historical Sketch 



of Henry s Contribution to the Electro- Magnetic Telegraph, 1879. No 



further report or particulars of Abraham Booth's work, aside from the 



same quotation in Fahie's book, was found to support the statement 



and it is not therefore considered to constitute adequate evidence of 



anticipation of Henry. 



5. Electromagnetic Induction 



Henry's first description of his experiments on self-induction is 

 included in his paper in Sillimans Journal of July, 1832. After de- 

 scribing experiments on mutual induction he proceeded with the 

 following : 



" I have made several other experiments in relation to the same subject, but which 

 more important duties will not permit me to verify in time for this paper. I may 

 however mention one fact w^hich I have not seen noticed in any work, and which ap- 

 pears to me to belong to the same class of phenomena as those before described; it is 

 this: when a small battery is moderately excited by diluted acid, and its poles which 

 should be terminated by cups of mercury, are connected by a copper wire not more 

 than a foot in length, no spark is perceived when the connection is either formed or 

 broken; but if a wire thirty or forty feet long be used instead of the short wire, though 

 no spark will be perceptible when the connection is made, yet when it is broken by 

 drawing one end of the wire from its cup of mercury, a vivid spark is produced. If 

 the action of the battery be very intense, a spark will be given by the short wire; in 

 this case it is only necessary to wait a few minutes until the action partially subsides, 

 and until no more sparks are given from the short wire; if the long wire be now substi- 

 tuted a spark will again be obtained. The etTect appears somewhat increased by coil- 

 ing the wire into a helix; it seems also to depend in some measure on the length and 

 thickness of the wire. I can account for these phenomena only by supposing the 

 long wire to become charged with electricity, which by its re-action on itself projects 

 a spark when the connection is broken." i" 



^^ Historical Sketch of the Electric Telegraph, by Alexander Jones, 1852, p. c,2. 



"SW, Vol. 1, p. 79. 



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