HENRY AND THE TELEGRAPH. 325 



provement in 1838, on the Schilling, Gauss, and Steinheil alphabets, of 

 employing instead of alternating signs (as in his tirst register), the simi^le 

 " dot-and-dash " alphabet in a single line.* 



As displaying the " movement of an age," it is interesting to observe 

 that these six capital steps were all effected within the fruitful period of 

 a single decade. If we except the first of these — the inaugurating ad- 

 vance, without Avhich no electro-magnetic telegraph would have been 

 practicable,t it will iirobably be diflicult for the impartial historian to 

 award to the succeeding five contributions their respective value and 

 just desert. 



The earlier needle type of the electro-magnetic telegraph, as developed 

 by Schilling and by Gauss, has found its special and apj^ropriate appli- 

 cation in extended ocean-lines ; and indeed without such development, 

 it is doubtful whether "we could have had a transatlantic telegraph. 

 It is well for the exclusive i)a.rtisans of the " American system " to 

 reflect that in the operation of these submarine cables there enters no 

 element of Morse's instrument. The receiving and indicating mechanism 

 devised by Gauss and Weber, and introduced some ten years eailier, is 

 essentially that in use to-day on either shore of the Atlantic Ocean. 

 The signals of the earlier invention are equal right and left deflections 

 of an exceedingly delicate reflecting galvanometer ; the signals of the 

 later invention are the unequal contacts of an electro-magnetic arm- 

 ature. 



Many other telegraphic developments — not within the object of this 

 summary, such as the various modifications of the galvanometer system, 

 the ingenious arrangements of dial indicators, and above all — as most 

 ingenious of all — the printing telegraphs, (originating as we have seen, 

 with Alfred Vail,) present what may be called liighly organized 

 varieties of the art; but varieties w^hich notwithstanding the rare 

 order of inventive intelligence expended ui)on them, and the great 

 value possessed by them in special applications, do not promise to 

 exercise a corresponding influence upon the future of telegraphy. The 

 wonders of multiplex telegraphy (the simultaneous transmission of two 

 or even four or more communications in either direction over the same 

 wire), and of vocal telegraphy (the transmutation and transmission of 

 human speech by electric waves in the telephone), lie still more beyond 

 the scope of this review. 



In conclusion, an early averment in this historic sketch, as to " the 

 growth of the electric telegrai)h," may be repeated in the language of a 

 later writer. " The history of the subject thus far shows us that no 

 single individual can justly claim the distinction of having been the 



* Professor Morse's first use of the alphabet was made in January, 18:?S. (New York 

 Journal of Commerce, January 2d, 18;i8 ; also Prime's Life of Morse, 8vo, New York, 

 187.1, p. 3:51. ) On the subjeet of "Alphabetic notation " see " Supplement," Note L. 



tWheatstone himself does not apjiear to have fully realized the signitieance and value 

 of Henry's researches till 18:57. The simple electro-chemical telegraph might have 

 been successfully developed without the discovery of the " intensity " magnet, and 

 may yet prove in practice a formidable competitor with it. 



