Acoustics

Friends of Natural Science, and here in Section 78), the determination of vibration numbers original: "Schwingungszahlen"; today commonly referred to as frequency for every tone through direct counting on a sounding body that can be lengthened or shortened at will (published in Gilbert’s Annals of Physics, Volume 5, Part 1, and here in the note to Section 29); the investigation of the speed at which vibrations occur in different types of gases, and the application of the results obtained thereby to the discrepancy between theory and experience regarding the speed of sound propagation in the air (in Voigt’s Magazine for Natural History, Volume 1, Part 3, and here in Section 204); and various other observations, as well as two inventions that do not belong here but rather to the practice of musical art: the Euphon and Clavicylinder The Euphon and Clavicylinder were friction-based instruments invented by Chladni; the Euphon used glass rods, while the Clavicylinder used a rotating cylinder to produce sound from metal bars., about which more will be said in the reports on the history of my discoveries.

To those friendly men who have in any way been helpful to me in the treatment of acoustic subjects, namely:

Through the joint performance of such experiments for which I did not have the apparatus, such as Mr. Chief Medical Councilor and Professor Hermbstädt in Berlin, and Mr. J. C. Ayke in Danzig during the experiments on the tones to be obtained by burning hydrogen gas in a tube This refers to the "singing flame" phenomenon, and Professor von Jacquin in Vienna during the experiments on the speed of vibrations of various types of gases;

Through the permission to use a public library at will, even at otherwise unusual times, such as the supervisors of the excellent Ducal Library in Stuttgart, in which I found everything I could wish for from the writings of learned societies and other works belonging to the practice of various sciences—at least up to the year 1792—most completely gathered together next to the Göttingen Library; whereas in some libraries, of which far more praise is usually made, I asked for them in vain;