292 HENRY AND THE TELEGRAPH. 



graph was first worked by a galvanic current from a battery, and after- 

 ward for convenience by the secondary cnrrent from a magneto-electric 

 apiiaratus; to which Ganss adapted an arrangement of commutator, 

 whereby the direction of the induced current could be instantly reversed 

 by a touch of the finger. The alphabet of signs was made up of differ- 

 ing combinations of right and left deflections of the needle. Weber ap- 

 l^lied to the signaling device a delicate apparatus for setting off a clock 

 alarm.* 



1836. Prof. C. A. Steinheil, of Munich, at the request of Gauss, (who 

 was absorbed in more abstract researches on magnetism,) in 1834, under- 

 took to develop and improve his arrangement ; and in 1830 had construct- 

 ed a similar galvanometer telegraph line between Munich and Bogen- 

 hausen, a distance of about two miles, t Employing a greater power he 

 arranged at the receiving station the magnetic bar or double bars of the 

 galvanometer with a larger sweep, so that two bells of differing tones 

 should be struck thereby ; and he thus produced an acoustic telegraph 

 (five years later than Henry's), capable of audible language, and dis- 

 pensing with the occasion for any call-alarm. To the adjacent ends of 

 the two magnetic bars having opposite i)olarities, but oscillating within 

 the same coil, he applied fountain peus or marking-points so as to make 

 X)ermanent alternating dots on a fillet of paper carried under them by 

 the regular movement of clock-work, in the manner long familiarly em- 

 ployed in self-registering meteorological and other instruments. Al- 

 thongh Dyar, on Long Island, had devised a chemical register as early 

 as 1828, and had partly executed it by a successful trial, this double 

 magnet of Steinheil appears to constitute the earliest operative applica- 

 tion of an automatic record to the electric, or to the electro-magnetic, 

 telegrai)h. Steinheil also improved somewhat on the alx)habet of Gauss, 

 though adopting substantially the same system. | 



In the following year, 1837, he made another most important improve- 

 ment in practical telegraphy, by the unexpected discovery that even the 

 single circuit of a to and fro line could be further simplified b}^ the 

 suppression and economy of one-half of its wire.§ 



* Gottingische Gelclirte Anzeigen, Aug. 9, 1834, part ii, No. 128, pp.1272, 1273. And 

 Foljjteclmischcs Cenfral-BIatt, Juue, 1838, Jabrgaug iv, No. 31, pp. 487-496. 



t Accorfling to Dr. Hamel of St. Petersburg, in the early part of July, 1837, "Stein- 

 heil, at Munich, had completed the connection of his house in the Lerchenstrasse with 

 the building of the Academy of Sciences, and with the Royal Observatory at Bogen- 

 hausen, by "means of 36,000 feet of wire for conducting the current both ways, the 

 wires being suspended in the air." {Journal of Society of Arts, July 29, 1859, vol. vii, 

 p. 609.) 



t Steinheil remarks : "As long as the intervals between the separate signs remain 

 equal, they are to be taken together as a connected group, whether they be pauses be- 

 tween the tones, or intervals between the dots marked down. A longer pause separ- 

 ates these groups distinctly from each other. We are thus enable I, by approx^riately 

 selected groups thus combined,to form systems representing the letters of the alpha- 

 bet, or stenogra]ihic characters, and thereby to repeat and render permanent at ail 

 parts of the chain whore an apparatus like that above described is inserted, any in- 

 formation that we transmit. The alphabet that I have chosen represents the letters 

 that occur the oftenest in German by the simplest signs." (Sturgeon's Annals of Elec- 

 tricity, etc. April, 1839, vol. iii, j). 520.) 



^" In 1837 Professor Steinheil operated a telegraph line between Munich and Bogen- 



