[73] Sir John Herschel and Sir C. Wheatstone, I believe, made this experiment independently.

[74] A subject to be dealt with in Chapter IX.

[75] Nor indeed any of those tones whose rates of vibration are even multiples of the rate of the fundamental.

[76] According to Kolliker, this is the number of fibres in Corti’s organ.

[77] The comparison employed by Mr. Sedley Taylor appeals with graphic truth to a mountaineer. Considering, the above curve to represent a mountain-chain, he calls the discords peaks, and the concords passes.

[78] This supposition is of course made for the sake of simplicity, the real period of oscillation of a pendulum 28 feet long being between two and three seconds.

[79] This figure corresponds to the interval 15:16. For it and some other figures, I am indebted to that excellent mechanician, M. König, of Paris.

[80] For some beautiful figures of this description I am indebted to Prof. Lyman, of Yale College.

[81] Mr. Sang, of Edinburgh, was, I believe, the first to treat this subject analytically.

[82] This able paper was the starting-point of the experiments on sensitive flames, recorded in Chapters VI. and VII.; the researches of Thomas Young and Savart being the starting-point of the experiments on smoke-jets and water-jets.—J. T.