The 



and a positive current is transmitted. If a piece of the breadth of the 

 key be cut out of the edge of the frame of depth equal to the play of 

 the key, no motion of the lever takes place. A second similar rect- 

 angular frame inside the first may be depressed and give a negative 

 current, or again may have a piece cut out and give no current at all. 

 Tims one key depressed can give any of the three possible signals on 

 the first wire. With three pairs of such rectangular frames and 27 keys 

 all the possible combinations of signals can be sent through the triple 

 wire. The keys may be given any letters or numbers, four wires and 

 eight rectangular level frames on the same axis would give 81 signals. 

 Elsewhere in the paper (p. 29) Galton indicates how with eight frames, 

 two wires only, but two battery strengths for each wire, five signals 

 might be got on each wire and so twenty-five signals in all. This 

 roughly describes his third section, the determination of the proper 

 movements of the needles for any given letter by touching a key. In 

 his first section he considers how the weak movements of a needle may 

 govern the movements of a heavy arm. He does not achieve this, as 

 we might anticipate, by electromagnets, but, discarding these, by a 

 somewhat elaborate mechanical device, which directs in a given manner 

 the energy of wheels kept rotating as nearly uniformly as possible. 

 We must refer the reader for the details of this part of the teletype, as 

 well as for those of the manner in which the appropriate letters are to 

 be actually printed, to the pamphlet itself; they have now only historical 

 interest, but they suffice to indicate a mechanical versatility which was 

 later to come to fuller fruition. Various additional possibilities are 

 then indicated, thus, on making certain signals, mechanical effects 

 other than printing letters, e.g. the sounding of a bell, can be obtained ; 

 methods are given by which the combination of one signal followed 

 by a letter shall print a capital or a figure; and again processes fin- 

 messages to be printed in cipher are indicated. 



Lastly Galton's concluding words may be cited here, for they 

 anticipate much that was to come later the transference of the tele- 

 graphs to the Post Office, and the modern development of the telephone: 



"If telegraphs, that worked and printed satisfactorily were once found practicable, 

 most large houses, public and private, would soon become supplied with them. The 

 communication being so immediate, answer following question as soon as it is put, 

 affords much more nearly the advantage of a personal communication than the best 

 regulated post office ever could. Any scheme to introduce telegraphs generally, would 



