Ernst Mach and The Mach Number: Photographische Fixirung der durch Projectile in der Luft eingeleiteten Vorgänge [in] Annalen 32. . . . From the library of Lord Rayleigh

Mach, Ernst (1838-1916) & Peter Salcher (1848-1928). Photographische Fixirung der durch Projectile in der Luft eingeleiteten Vorgänge. In Annalen der Physik und Chemie, n.s., 32 (1887): 277-291; plate. Whole volume. viii, 704pp. 5 folding plates (including the Mach plate), text illustrations. 213 x 132 mm. Original cloth, spine faded and with a few chips at extremities, corners a bit worn. Endpapers toned but very good. From the library of Nobel Laureate John William Strutt, third Baron Rayleigh (1842-1919), with his pencil signature ("Rayleigh") on the front flyleaf.

Second printing, published the same year that the paper appeared in the Sitzungsberichte der kaiserlichen Akademie der Wissenschaften zu Wien; a printed note at the head of the paper reads "Aus dem 95. Bde. der Sitzungsber. der kais. Acad. der Wiss. zu Wien vom 21. April 1887; mitgetheilt von den Herren Verf." [From the 95th volume of the session reports of the Imperial Academy of Sciences in Vienna on April 21, 1887; communicated by the gentlemen authors]. From the library of John Strutt, third Baron Rayleigh, who received the Nobel Prize for physics in 1904 for "his investigations of the densities of the most important gases and his discovery of argon in connection with these studies."

Mach's classic paper contains the first photograph of a shock wave in front of an object (in this case a bullet) moving at supersonic speed, and the first mathematical formula describing the physics of this wave. "The angle , which the shock wave surrounding the envelope of an advancing gas cone makes with the direction of its motion, was shown to be related to the velocity of sound and the velocity of the projectile as sin = / when > . After 1907, following the work of Ludwig Prandtl at the Kaiser Wilhelm Institut für Strömungsforschung in Göttingen, the angle was called the Mach angle. Recognizing that the value of / (the ratio of the speed of an object to the speed of sound in the undisturbed medium in which the object is traveling) was becoming increasingly significant in aerodynamics for high-speed projectile studies, J. Ackeret in his inaugural lecture in 1929 as Privatdozent at the Eidgenössischen Technische Hochschule, Zürich, suggested the term ‘Mach number' for this ratio. The Mach number was introduced into the literature in English by the late 1930s and since the end of World War II has taken on considerable importance in theoretical and fluid dynamics" (Dictionary of Scientific Biography). Anderson, Hist. Aerodynamics, p. 376.