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 (н 1), 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. The last automaton of Hero to which I shall refer is perhaps the most ingenious of all, and it is one that those who were present when Brother Manning gave us his discourse on Robert-Houdin have already seen, I mean the little figure whose head cannot be severed from his body no matter how many times a knife be passed through his neck. Thanks to the kindness of my good friend I can show you one of these beautiful figures presented to me by him, and it will, I think, be of interest to him and to you to know that this device was invented nearly 2,000 years before Robert-Houdin was born, and a description of it with accompanying figures may be seen to-day in the British Museum in a Greek manuscript of the fifteenth century, which is a copy of Hero's rapiraλia, and I now throw on the screen a carefully made facsimile (Fig. 12) of the figure given in that manuscript (which is known as No. 5605 of the Harleian Collection). The head of this figure, which is otherwise separate from it, is attached to it by a peculiar shaped wheel pivotted between the shoulders of the body. This wheel may be described as a circular disc having an expanded rim so that a section taken through a radius would be of the form of the letter T, out of this wheel three nearly semicircular gaps are cut, each occupying sixty degrees of the circumference, and therefore leaving three portions of the rim, each also of sixty degrees. The neck attached to the head is fitted with a hollow T shaped circular groove into which the T ended arms of the wheel |