CATALOGUE. ACUSTICS, PROPAGATION OF SOUKD. 



265 



Observed the time occupied in the return of an echo. 

 Found the velocity from 1 1 50 to 1526 feet in a second. 



Hawksbee on sound in condensed and rare- 

 fied air. Ph. tr. 1705. XXIV. I902. 1709. 

 XXVI. 367. 



A bell was heard at the distance of 30 yards when the air 

 was in its common state, at 60 with the force of two at- 

 mospheres, at 90 with the force of three : beyond tliis the 

 intensity did not much increase. A vacuum was made be- 

 tween two receivers, the bell being within the innermost, 

 and the sound was not transmitted. 



Hawksbee on the propagation of sound 

 through water, Ph.tr. 1709- XXVI. S71. 



*Derhain de soni motu. Ph. tr. 1708. 

 XXVI. 2. 



Velocities observed by different persons. 



Roberts. Ph.tr. n. 209 I'JOO 



Boyle. Essay on motion 1200 



, Walker. Ph.tr. 1338 



Mersennus, Balistica 1474 



Flamsteed and Hallcy 1142 



Florentine academicians 1148 



Cassini and others, Duhamel. H. A. 1 172 

 Derham 1142 



Derham found the effect of the wind, but not of any 



changes of weather. 



Mairan. A. P. 1737. II. 1. 

 Cassini on the propagation of sound. A. P. 

 1738. 128. H. 1. 



Makes the velocity 1 107 feet. 



Cassini. A. P. 1739. 



.Biancoiii delLa diversa velocita del suono. 



Venice. 

 Bianconi on the velocity of sound. C. Bon. 



II. i. 3G5. 



In summer, the thermometer being at 20°, 76 vibrations 

 of the pendulum elapsed while a sound passed over )3 

 miles; in winter 79 seconds, the thermometer being at 

 — 1.2°. In a cloud or mist 155" elapsed while the sound 

 passed and repassed. Hence the air should expand 

 ^ for 21.2°, or ^^ for \° of the thermometer employed, 

 probably Reaumur's, which is j^ for l°of Fahrenheit. The 

 mean difference of the temperature of the air was probably 

 somewhat less than is sup)X)sed, perhaps 17° or 1S°. 



VOL. n. 



Zanotti on the intensity of sound in air of 



different densities. C. Bon. II. Coll. 



Ac. X. 

 fEulcr on the propagation of pulses. N. C. 



Petr. I. 67. 

 jE)(/( ri conjectura physica circa propagatio- 



neni soni et luminis. 4. Berl. 175O. Opusc. 

 Euler on the propagation of sound. A. Berl. 



17.0 9. 

 Euler on the propagation of agitations. M. 



Taur. II. ii. 1. 

 Euler on the generation and propagation of 



sound. A. Berl. 1765. 33.5. 

 n7«A/erTentamina circa soni celeritatem. 4. 



Leipz. 17(33. 

 Lagrange. M. Taur. I. II. 

 fLamberton the velocity of sound. A. Berl. 



1768. 70. 1772. 103. Hoz. XVIII. 126. 



Thinks that the air contains about i of foreign matter. 



Blagden. Ph. tr. 1784. 201. 



Observes, that many witnesses agreed that they heard the 

 whizzing of a very distant meteor at the instant of its ap- 

 pearance ; but that this was probably a fallacy. 



PerrolJcon the propagation of sound in gases. 

 M. Tur. 1786. Ul. Coir. 1. 1790. V. Corr. 

 195. Roz, XXIII. 378. Journ. Phys. 

 XLIX. 382. Nich. I. 411. Gilb. III. 167. 

 IV. 112. 



Founl it very weak in hydrogen gas. 



W^unsch on tiie velocity of sound in wood. 

 A. Berl. Dciitsch. abii. 17S8. 87. 



Sound was conveyed instantaneously through 3fi con- 

 nected laths of 24 feet each, or8S4 feet, if not through 7?. 

 which was the whole number employed. 



Robison. Enc. Br. XVllI. Art, Trumpet arti- 

 culate. 



Alleges many facts in favour of the nondivergence of 

 sound and waves. He observes, that "all the general co- 

 rollaries respecting the. lateral divergence of waves are 

 little more than sagacious guesses." 



fLamarck on the medium of sound. Journ. 

 Phys. XLIX. 397. 



Thinks it a medium more subtile 'ban air. 



M m 



