240 ELECTRO-TELEGRAPHY 



character in solution in water. The compound selected by Mr. Bivin is ferrocyanide of 

 potassium. With a solution of this, ho saturates a long ribbon of paper, similar to 

 that employed in Morse's telegraph. Ho causes the paper B (jig. 813) to pass over a 

 drum of brass R, between the metal of R and an iron point or stylus r. The electric 

 current enters the apparatus by the point r, passes through the solution of ferrocyanido 

 of potassium, with which the paper it is saturated, and out by the spring r', which is in 

 metallic contact with the drum R. Decomposition takes place, and the well-known 

 ferrocyanide of iron (Prussian blue) is formed at the point of contact of the iron stylus 

 i with the paper, the iron of the compound being supplied by the stylus itself. The 

 paper is carried on by ordinary mechanism ; and a dot-and-dash alphabet is formed, 

 according to the duration of contacts at the sending station. There is a single-wire 

 und a double-wire code ; and the signals appear as deep blue marks upon the paper. 

 Supplies of paper saturated with the solution are kept in reserve. This is unques- 

 tionably a telegraph of extreme simplicity. It has been employed with much success. 



Mr. Whitehouse prepared for the Atlantic Telegraph a system in which motion 

 and chemical action each play their part. The secondary currents that ho employed 

 were not able to produce the chemical decomposition that he requires for his signals. 

 He therefore received them in a very sensitive relay, either an electro-magnet or a 

 multiplier. The relay was a contact-maker, and connected the necessary number of 

 local batteries with the printing apparatus, which consists of a ribbon of paper, satu- 

 rated with a chemical solution and passing between a drum and a steel point. 



We should exceed our limits were we to attempt the description of some of the many 

 other forms that have been proposed. The above are good illustrations of the leading 

 principles, and are all in successful use. Some telegraphs will print in ordinary cha- 

 racters ; this result is only attained by much complexity, and its value is more than 

 questionable, it being as easy to learn a new code as a new alphabet ; telegraph 

 clerks read their signals as readily as they read ordinary writing or printing, and they 

 acquire their knowledge in a very short time. Hence probably it is that telegraphs to 

 print in ordinary characters are but little known in real practice ; nevertheless, some 

 very promising instruments of the class have been produced by House, and especially 

 one more recently by Hughes, both of the United States. 



The following remarks on printing telegraphs have been handed to us, and wo give 

 them insertion as they appear to point to an improved system : 



* The needle and bell instruments, however, have hitherto transmitted messages with 

 far greater rapidity than has been possible by the ink writer ; but the advantage of a 

 system which is self-recording recommends itself to all, inasmuch as, without some 

 record, it is impossible to trace an error to its source, either at the sending or receiving 

 station. 



4 The ink-writer now in use by the Telegraph Department of the Post Office, can 

 only record the telegraphic signals by breaking a line formed longitudinally, on a 

 band of paper, the operator, whether skilful or unskilful, breaking that line where ho 

 pleases into the requisite " dots" and " dashes." Thus, apart from the time occupied 

 in writing or drawing the " dashes" which, being formed of strokes three times the 

 length of the strokes forming the " dots," require three times longer to draw them than 

 the ''dots" a certain amount of skill is needed to work the instrument, and, of 

 course, accuracy is not insured. Indeed, a short " dash " followed by a long "dot" 

 may be read either as two dashes or two dots. 



* Attempts to remedy this confusion have been made by Mr. Herring, who has en- 

 deavoured to unite the chief advantages of the Morse ink-writer, which was the 

 favourite instrument of the Electric Company, with the speed of the boll-instrument, 

 which was an equal favourite with theMagnetic Company ; and, without necessitating any 

 now method of sending or receiving messages, but simply by substituting for the double 

 boll a printing instrument, ho appears to have perfectly succeeded. Instead of wast ing 

 the currents upon merely fleeting appeals to the eye by needle, or to the ear by bell, 

 or adopting an uncertain and tedious method of writing the signs in ink, he has con- 

 trived a telegraph printing instrument, whereby the signs may be instantaneously 

 stomped in printing ink, on the paper, with their actual types, thus insuring positive 

 correctness. This instrument which costs very little more than that now used by the 

 Telegraph Office, has been described by Mr. Scudamoro as ' much superior to the 

 numerous methods which have been brought forward from time to time during the 

 last twenty years,' and he adds, that it ' admits of the signs being produced faster and 

 in less compass. 



* The telegraphic instrument invented by Mr. Herring was so constructed as to pro- 

 duce the dot and the dash of the Morse code in such a manner that one could never 

 be mistaken for the other. This was effected by the use of two distinct levers : an 

 arrangement which also permitted the dash to bo made vertical, instead of horizontal, 

 and to be produced instantaneously, instead of by continued pressure, thus saving tho 

 time of the operator, and diminishing tho length of tho message slip. 



