Under this title and that of ANDROIDES full credit was allowed in the Encyclopaedia Britannica to the story of M. de Kempell's mechanical chess-player, and a detail at some length was given of the feats of that figure, as well as of some other surprising automata. No man more readily admits the powers of the skilful mechanician than the writer of this short article; but having many years ago detected the imposition which was practised on the public in some parts of Scotland by a circumferaneous mountebank, who exhibited a figure apparently capable of writing a certain number of words, he has ever since suspected imposture in all automata which appear to have the power of varying their motions according to circumstances. With respect to the chess-player, there is now sufficient evidence that his suspicions were well founded.

In the description of this figure (Encycl. Vol. I. p. 787.), "it is said, that the automaton could not play unless M. de Kempell or his substitute was near it to direct its moves. A small box during the game was frequently consulted by the exhibiter; and herein consisted the secret, which he said he could in a moment communicate." The secret was indeed simple: "A well taught boy, very thin and small of his age, was concealed in this box almost immediately under the chess-board, and agitated the whole machine." This we learn from Thomas Collinson, Esq.; who was let into the secret at Dresden by a gentleman of rank and talents, named Joseph Frederick Freyherre, by whom the vitality and soul of the chess-playing figure had some time before been completely discovered. Mr Collinson, finding that Dr Hutton had given the same credit with us to the reality of mechanical chess-playing, undeceived his friend, by communicating the discovery of Freyherre in a letter, which the Doctor has with great propriety published in the Addenda to his Mathematical Dictionary. Mr Collinson adds, and we doubt not with truth, that, "even after this abatement of its being strictly an automaton, much ingenuity remains to the contriver." This was in some degree true of the mechanism of the writing figure, of which the compiler of this article detected the bungling imposture of the two exhibitors. The figure itself, with all the principles of its motion, were very ingeniously constructed; but the two men who exhibited it were ignorant and awkward, and could not conceal from a scrutinizing eye, that the automaton wrote sometimes well and sometimes ill, and never wrote at all when they were both present to the company. It was by inflicting upon seeing them both together, and threatening to expose the cheat to the whole town, that the present writer prevailed upon him who appeared to be the principal exhibiter, to confess in private that his companion was concealed behind a screen, and to show how, from thence, he directed the movements of the figure.

CONJUGATE AXIS, or Second Axis, in the ellipse and hyperbola, is the diameter passing through the centre, and perpendicular to the transverse axis; and is the shortest of all the conjugate diameters.

TRANSVERSE AXIS, in the ellipse and hyperbola, is the diameter passing through the two foci and the two principal vertices of the figure. In the hyperbola it is the shortest diameter, but in the ellipse it is the longest.

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