From the above description it would appear that a still greater invention than a flying automaton was made by Archytas, for in an apparatus “_so nicely balanced by weights and put in motion by hidden and inclosed air_,” we have a very fair forecast of the modern aërostat or balloon, filled with gas and balanced by ballast. There cannot be any doubt but that the accounts of these very early machines (if such ever existed at all), have been greatly exaggerated during the process of being handed down through long ages of ignorance and credulity; but we may now enter upon surer ground although still very ancient. In the reign of Ptolemy Euergetes II. (Ptolemy VII.), about 150 years B.C., there lived at Alexandria that great genius of mechanical science, Hero; and his remarkable book “Spiritalia,” of which I am able to show you several copies to-night, is itself a great storehouse of ingenuity in the construction of automata of very various forms and principles. This remarkable man was, if not the inventor, the first describer of the siphon in both its typical forms, the syringe, the well-known portable shower-bath, the clack valve, the fire engine, even with that mechanical refinement, an air vessel for insuring a continuous stream, a self-trimming lamp, the steam blowpipe, the pneumatic fountain called after his name, a steam engine, and last if not least, the penny-in-the-slot automatic machine for obtaining a drink, or, may be, a charge of scent. I propose now to show you on the screen some photographic reproductions of pages in his book, some taken from the Latin edition of Commandinus, published at Urbino in 1575, and some from the Italian edition of Alessandro Georgi, printed at the same place in 1592, some from the fine edition of Aleotti, published in 1589, and others from the Amsterdam version of 1680, all of which editions I am able to show you. I have, moreover, copied some from manuscripts in the British Museum, of the fifteenth and sixteenth centuries, of which there are four in the National Library, _i.e._, two in the Harley Collection and two among the Burney manuscripts. [Illustration: Fig. 1.] The first illustration I shall show you from Hero’s work is a bird which, by means of a stream of water, is caused to pipe or sing. This little automaton consists of a pedestal (A B C D) (Fig. 1), which is in reality a water-tight tank fitted with a funnel (E), the stem of which reaches nearly to the bottom; to the right of this there is a little bush on which sits a bird, and a tube (G H) leads up from the roof of the tank and terminates in a little whistle, the end of which dips into a cup (L) containing water. When water is poured into the funnel, the air in the tank is driven out through the tube and whistle (G H) and, bubbling through the water, sounds as if the bird were singing. Thus the well-known bubbling bird-whistle dates back to a century and a half before the Christian era or earlier.