In an article on page 302, this volume, SCIENTIFIC AMERICAN, on " the cause of sound and music," the opinion was expressed that the different qualities of sound (those of voices and various instruments) were caused by the form of the sound waves or vibrations. Experiments have recently heen made to prove the correctness of this view ; and an account of these has been published in the Franklin Jm,rnal (page 407) for this month. This is taken from the Cosmos—a European publication. The experiments were made by M. Leon Scott, whose apparatus consisted of a tube flaring out widely at one end, like a trumpet, and closed at the other end by a thin membrane, to the middle of which was attached a very light pencil. This tube concentrated the sounds which entered by its wide mouth, and the vibrations of the membrane thus produced \.uru written with the pencil upon paper, which was carried with a uniform motion under the pencil by clockwork. The figures formed by the pencil on the paper were very different, both in form and dimensions, according as wind or stringed instrument5, or the human voice were used. It was established by experimcnt that the series of vibrations formed by the sound of an instrument or voice was more regular in proportion as it was agreeable to the ear, or what is termed " pure." Shrill cries, harsh sounds, and disagreeable voices produced very irregular and unequal marks— ungraceful lines—upon the paper.
This article was originally published with the title "Form of Sound Waves" in Scientific American 13, 44, 345 (July 1858)