Analysis of an early measurement of the speed of sound propagation in the atmosphere

Spanish and French scientists made a determination of the speed of sound close to Quito (Ecuador) in 1738. There was a particular interest in this measurement at that time because it was thought that the proximity of the Equator and the great altitude would have a major influence on this magnitude. The difference in time between the perceptions of the flash of a gunshot and of the corresponding sound was measured at two different sites. At one of them, Jorge Juan and Louis Godin obtained a value of 341 m/s for the speed of sound, and at the other, Antonio de Ulloa and Pierre Bouguer deduced a value of 348 m/s. Juan and Ulloa published these experiments in their book “Observaciones Astronomicas y Phisicas” (1748). They also presented possible applications of these studies of sound propagation to geometry, navigation, and warfare.