Thus prohibited by an authority to which he yielded implicit obedience from trying further experiments at the risk of his neck, he restricted his inventive faculty to safer channels, and determined that the structure he was superintending should reproduce, as far as possible, all the peculiarities of the Athenian Theatre. Amongst other things, he studied attentively the subject of the _echeia,_ or sonorous vases, which, in that vast theatre, propagated and clarified sound; and though in its smaller representative they were not needed, he thought it still possible that they might produce an agreeable effect But with all the assistance of the Reverend Doctor Opimian, he found it difficult to arrive at a clear idea of their construction, or even of their principle; for the statement of Vitruvius, that they gave an accordant resonance in the fourth, the fifth, and the octave, seemed incompatible with the idea of changes of key, and not easily reconcilable with the doctrine of Harmonics. At last he made up his mind that they had no reference to key, but solely to pitch, modified by duly-proportioned magnitude and distance; he therefore set to work assiduously, got a number of vases made, ascertained that they would give a resonance of some kind, and had them disposed at proper intervals round the audience part of the building. This being done, the party assembled, some as audience, some as performers, to judge of the effect. The first burst of choral music produced a resonance, like the sound produced by sea-shells when placed against the ear, only many times multiplied, and growing like the sound of a gong: it was the exaggerated concentration of the symphony of a lime-grove full of cockchafers,{1} on a fine evening in the early summer. The experiment was then tried with single voices: the hum was less in itself, but greater in proportion. It was then tried with speaking: the result was the same: a powerful and perpetual hum, not resonant peculiarly to the diatessaron, the diapente, or the diapason, but making a new variety of continuous fundamental bass. 1 The drone of the cockchafer, as he wheels by you in drowsy hum, sounds his _corno di bassetto_ on F below the line.-- Gardiner's Music of Nature. 'I am satisfied,' said Lord Curryfin, 'the art of making these vases is as hopelessly lost as that of making mummies.' Miss Niphet encouraged him to persevere. She said: 'You have produced a decided resonance: the only thing is to subdue it, which you may perhaps effect by diminishing the number and enlarging the intervals of the vases.' He determined to act on the suggestion, and she felt that, for some little time at least, she had kept him out of mischief. But whenever anything was said or sung in the theatre, it was necessary, for the time, to remove the _echeia_. CHAPTER XVIII LECTURES--THE POWER OF PUBLIC OPINION--A NEW ORDER OF CHIVALRY