[236] An Account of the Speaking-trumpet, as it hath been contrived and published by Sir Samuel Morland, knight and baronet, together with its use both at sea and land. London, 1671. An extract from it may be seen in the Phil. Trans., No. 78, p. 3056. [237] Among the antiquities of Syracuse in Sicily, one beholds with wonder chambers and galleries which are hewn out in the solid rock, and particularly a grotto, from which arises a winding passage, that becomes upwards still narrower. Ancient tradition says that this was a prison, which the celebrated tyrant Dionysius caused to be built for state prisoners, that in an apartment of his palace, which stood over the narrow end of the passage, he might hear everything the prisoners said, or what plots they formed against him. This grotto therefore is called _Orechio di Dionysio_, or _la grotta della favella_; _auris Dionysii_, the ear of Dionysius. Many travellers and others formerly imagined that this passage was an ingenious imitation of that part of the human ear called the helix, which was first remarked by Alcmaon the Pythagorean. This is the account given by Kircher, who was there in the year 1638. See his Phonurgia (published 1673), p. 82, where there is a figure of it. In later times, however, this grotto has been examined with more skill and acuteness by people less subject to prejudice, and since that period the supposed wonder has been lessened. The rock consists of limestone, at least I conclude so from what is said by Brydone, who found it everywhere full of cracks and fissures. The stones of which Syracuse was built were hewn from the rock; and hence have been formed these chambers or openings, like those found in the neighbourhood of other ancient and modern cities, such as Rome, Naples, and Maestricht. Many of these, in the course of time, have been employed as prisons, or used as burying-vaults. The above-mentioned passage, which has excited so much wonder, is not properly spiral, and is of such a figure that it may have been produced either by accident or through the whim of the workmen employed to hew out the stones. The double echo which Kircher assures us he heard in the grotto was not remarked by Schott, who was there in 1646, as he expressly says, in opposition to his brother jesuit, in his Magia Naturalis. In the accounts still remaining of Dionysius we find mention of an astonishing prison, which is well described by Cicero in his fifth oration against Verres: “You have all heard of,” says he, “and most of you know the prison (lautumias) of Syracuse. It is an immense and magnificent work, executed by kings and tyrants; the whole is sunk to a wonderful depth in the rock, and has been entirely cut out by the labour of many hands. No place so secured against an escape; no place so enclosed on all sides; no place so safe for confining prisoners can be either planned out or constructed.” But it cannot be proved, and according to