Singular effects in nature depending on sound--Permanent character of speech--Influence of great elevations on the character of sounds, and on the powers of speech--Power of sound in throwing down buildings--Dog killed by sound--Sounds greatly changed under particular circumstances--Great audibility of sounds during the night explained--Sounds deadened in media of different densities--Illustrated in the case of a glass of champagne--and in that of new-fallen snow--Remarkable echoes--Reverberations of thunder--Subterranean noises--Remarkable one at the Solfaterra--Echo at the Menai suspension bridge--Temporary deafness produced in diving-bells--Inaudibility of particular sounds to particular ears--Vocal powers of the statue of Memnon--Sounds in granite rocks--Musical mountain of El-Nakous. Although, among the phenomena of the material world, there is scarcely one which, when well considered, is not an object of wonder, yet those which we have been accustomed to witness from our infancy lose all their interest from the frequency of their occurrence, while to the natives of other countries they are unceasing objects of astonishment and delight. The inhabitant of a tropical climate is confounded at the sight of falling snow, and he almost discredits the evidence of his senses when he sees a frozen river carrying loaded waggons on its surface. The diffusion of knowledge by books, as well as by frequent communication between the natives of different quarters of the globe, has deprived this class of local wonders of their influence, and the Indian and the Scandinavian can visit each other’s lands without any violent excitement of surprise. Still, however, there are phenomena of rare occurrence, of which no description can convey the idea, and which continue to be as deeply marked with the marvellous as if they had been previously unknown. Among these we may rank the remarkable modifications which sound undergoes in particular situations and under particular circumstances. In the ordinary intercourse of life, we recognize individuals as much by their voice as by the features of their face and the form of their body. A friend who has been long absent will often stand before us as a stranger, till his voice supplies us with the full power of recognition. The brand imprinted by time on his outer form may have effaced the youthful image which the memory had cherished, but the original character of his voice and its yet remembered tones will remain unimpaired.