The Reawakening : Scientific Exploration 213
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 rectangular 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. Thus 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 telotype, 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 for 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 telegraphs 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