Ernst Mach about supersonic waves excited by gunfire, 2 First Offprints, 1888/89

Ernst MACH: ÜBER DIE FORTPFLANZUNGSGESCHWINDIGKEIT DES DURCH SCHARFE SCHÜSSE ERREGTEN SCHALLES. Mit 3 Textfiguren. Aus den Sitzungsberichten d. kais. Akademie d. Wissenschaften in Wien. Mathem.-naturw. Classe; Bd. XCII. Abth. II. a. October 1888. (Vorgelegt in der Sitzung am 11. October 1888.) And: ÜBER DIE SCHALLGESCHWINDIGKEIT BEIM SCHARFEN SCHUSS NACH VON DEM KRUPP'SCHEN ETABLISSEMENT ANGESTELLTEN VERSUCHEN. Mit 1 Textfigur. Aus den Sitzungsberichten d. kais. Akademie d. Wissenschaften in Wien. Mathem.-naturw. Classe; Bd. XCVIII. Abth. II. a. October 1889. (Vorgelegt in der Sitzung am 10. October 1889.) Vienna: Verlag der Akademie der Kaiserlichen Wissenschaften (in commission at F. Tempsky [K.k. Hof- und Staatsdruckerei]) 1888 and 1889.

8to (22,6:15,1 cm). 8; 20 pages. Letterpress on machine paper, in private half cloth binding with the original wrappers (of paper 1) and cut out with title-printing (of paper 2) respectively tipped-on cardboard covers.

Two first offprints of early seminal papers by Ernst Mach about supersonic waves excited by gunfire.

Contents: The first of the papers „Über die Fortpflanzungsgeschwindigkeit …“ is a critical reply by Mach to a seminal paper by the French ballistician Hyppolite Sebert titled „Sur le mode de propagation du son des détonations, d'après les expériences faites au camp de Chàlons par M. le Capitaine Journée“, published only shortly before. Mach here claims priority to Sebert in having obtained indications of the forms of the waves excited in the air by projectiles when moving with velocities higher than the normal velocity of sound in the air. Doing so he points to a study conducted by him together with Ernst Salcher and published as „Photographische Fixierung der durch Projectile in der luft eingeleiteten Vorgänge“ in 1897 and nowadays considered as pivotal, in which he also presented the first photograph of a shock wave in front of an object moving at supersonic speed. He also accuses Sebert of having made incorrect calculations and provides corrections.

In the second paper titled „Über die Schallgeschwindigkeit …“ Mach analyses data on this matter provided to him by the Krupp firing range in Meppen.

Condition: Original front and rear wrapper of the first paper tipped-on grey cardboard, a cut out with the title printing of the second paper additionally tipped-on the front cover, front wrapper in parts dissolved,  cover slightly worn. Owner's stamp „G. Kerzdörfer / Kaiserslautern / Amselstr. 69“ on top right of front cover.

Rarity: RHB and JAP/APO (1988ff.) show no record of these offprints at all.