AUTOMATON 



275 



perly speaking, arc not older than wheel-clocks ; and that the more perfect structures 

 of this kind are subsequent to the general introduction of spn'w^-clocks. Many ac- 

 counts of ancient automata, such as the flying pigeon of Archytas of Tarentum, appear 

 to have been but poor mechanical contrivances. ' The Pneumatics of Hero of Alexan- 

 dria ' have been rendered accessible to the English reader by the translation of Mr. 

 Bennett Woodcroft. In this work will be found descriptions and drawings of several 

 curious contrivances which must be included amongst automata. The following, 

 amongst others, may be quoted : 



'An automaton which drinks at certain times only, on a liquid being presented 

 to it. 



1 An automaton which may be made to drink at any time on a liquid being pre- 

 sented to it, 



' An automaton which will drink any quantity which may be presented to it. 



1 An automaton, the head of which continues attached to the body after a knife 

 has entered the head at one side, passed completely through it, and out at the other ; 

 which animal will drink immediately after the operation.' 



Beckmann informs us, quoting from Plato, that Daedalus made statues which 

 could not only walk, but which it was necessary to tie, in order that they might not 

 move; and, on the authority of Aristotle, he speaks of a wooden Venus, and 

 remarks, that the secret of its motion consisted in quicksilver having been poured 

 into it. 



The moving power of almost all automata is a wound-up steel spring ; because, 

 in comparison with other means of giving motion, it takes up the smallest room, is 

 easiest concealed and set a-going. Weights are seldom employed, and only in a par- 

 tial way. The employment of other moving powers is more limited ; sometimes fine 

 sand is made to faU on the circumference of a wheel, by which the rest of the mecha- 

 nism is moved. For the same purpose water has been employed ; and, when it is 

 made to fall into an air-chamber, it causes sufficient wind to excite musical sounds in 

 pipes. In particular cases quicksilver has been used, as, for example, in the Chinese 

 tumblers, which is only a physical apparatus to illustrate the doctrine of the centre of 

 gravity. 



Fig. 100 exhibits the outlines of an automaton, representing a swan, with suitably 

 combined movements. The mechanism may bo described, for the sake of clearness 

 of explanation, under dis- 

 tinct heads. The first re- 

 lates to the motion of the 

 whole figure. By means of 

 this part it swims upon the 

 water, in directions changed 

 from time to time without 

 exterior agency. Another 

 construction gives to the 

 figure the faculty of bend- 

 ing its neck on several occa- 

 sions, and, to such an extent, 

 that it can plunge the bill 

 and a portion of the head 

 under water. Lastly, it is 

 made to move its head and 

 neck slowly from side to 

 side. 



On the barrel of the spring 

 exterior to the usual ratchet 

 wheel, there is a main- 

 wheel, marked 1, which works into the pinion of the wheel 2. The wheel 2 moves a 

 smaller one, shown merely in dotted lines, and on the long axis of the latter, at either 

 end, there is a rudder, or water-wheel, the paddles of which are denoted by the letter 

 a. Both of these rudder-wheels extend through an oblong opening in the bottom of 

 the figure down into the water. They turn in the direction of the arrow, and impart 

 a straightforward movement to the swan. The chamber in which these wheels re- 

 volve is made water-tight, to prevent moisture being thrown upon the rest of the 

 machinery. By the wheel 4, motion is conveyed to the fly-pinion 5 ; the fly itself, 

 6, serves to regulate the working of the whole apparatus, and it is provided with a 

 stop bar, not shown in the engraving, to bring it to rest, or set it a-going at pleasure. 

 Here, as we may imagine, the path pursued is rectilinear, when the rudder-wheels 

 are made to work in a square direction. An oblique bar, seen only in section at b, 

 movable about its middle point, carries at each end a web foot c, so that the direction 



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