The next automaton from Hero is very ingenious and interesting, because it combines hydraulic, pneumatic, and mechanical actions. Here (Fig. 9) is a figure of Hercules armed with a bow and arrow; there is also a dragon under an apple tree, from which an apple has fallen to the ground. Upon the apple being lifted, Hercules discharges the arrow at the dragon, which begins to hiss and continues to do so for some minutes. In this apparatus there is a double tank having a connection by a valve (H), which is attached by a cord to the apple (K), another cord, passing over a pulley, connects the apple with a trigger in the right hand of Hercules. Upon lifting the apple the trigger is released, and at the same time the valve is opened, allowing the water in the upper tank to flow into the lower, by which means air is forced through a tube (Z) into the dragon’s mouth, producing a hissing sound, and this will continue until the upper tank is empty. Here (Fig. 10) is Bate’s version of the same device, but very inferior to that from which it was taken. [Illustration: Fig. 10.] The next photograph is taken from another work of Hero’s, “_Quatro theoremi aggiunti a gli artifitiosi spiriti_,” a copy of which I have here (Fig. 11), and which was printed at Ferrara in 1589. [Illustration: Fig. 11.] This figure illustrates a very elaborate automaton, representing one of Vulcan’s workshops in which you will see a smith forging a piece of iron, and assisted by three hammermen. The smith first puts his iron in the fire and then lays it on the anvil when the hammermen begin to hammer it; then they leave off, and the smith turns round again to the fire. All these effects are produced by the machinery below the floor, and shown in the illustration. A shaft (A B) is driven by means of a water-wheel on the right, and on this shaft are projections or cambs which, by striking the ends of three levers (T, X, and V), pull the chains by which the arms of the hammermen are lifted. While this is going on the bucket (marked 20) is slowly filling, and when a sufficient weight of water has accumulated in it, it lifts the counterweight (17), and, in doing so, rotates the vertical shaft to which the figure of the smith is attached, turning him round to the fire, and at the same time, by swinging round the conduit pipe (H I), cuts off the water from the wheel, and the hammermen cease to work until the smith is again ready for them. I think you will agree with me that this machine offers very fair evidence of the mechanical ingenuity of a man who flourished more than 2,000 years ago.