470 SCIENTIFIC RECORD FOR 1882. 



operatioDS. It consists of a flask of 200 to 250 c. c. capacity, whose neck 

 carries a lateral tubulnre of small diameter, and is closed by a hollow 

 stopper carefully ground, which terminates in a straight tube carrying 

 a stopcock. From the side of this hollow stopi)er a tube jiasses, at- 

 tached to its interior, and long enough to reach to the bottom of the 

 flask. By rotating the stopper the opening into this tube may be 

 brought opposite the lateral tubulure. The volume of the flask having 

 been determined, the gas is introduced by the lateral tubulure until all 

 the air is displaced. The stopper is then turned, the barometer and 

 thermometer noted, and the balloon weighed, a similar flask being used 

 as a counterpoise. The results given show very considerable accuracy. 

 {Comptes Eendus, March, xciv, p. 026.) 



ACOUSTICS. 



Martini has studied the production of sound by the flow of liquids. 

 He used in his experiments long tubes of glass, two to six centimeters 

 in diameter, closed at the lower end by metallic disks two to three 

 millimeters thick, each pierced with a hole in the center, the diameter of 

 which was equal to the thickness of the plate. On filling such a tube 

 with water and allowing it to flow out through the plate, sounds are 

 produced like those of an organ pipe. As the water falls the sounds 

 do not fall uniformly in pitch as with the syren ; only a certain number 

 of definite sounds are produced, as is the case with an organ pipe. 

 Martini's results, which confirm essentially those of Savart, furnish a 

 method for determining the relative velocity of sound in two liquids. 

 By noting the lengths of two columns which yield the same note, the 

 velocities are obtained, since they are proportional to these lengths. 

 For alcohol of 36° the velocity was 1,288.5 meters; for absolute alcohol, 

 1,232.05 meters ; for ethyl ether, 1,144 meters ', and for i)etroleum of den- 

 sity 0.800, 1,354 meters. {J. Phys,, November, II, i, p. 574; Nature, De- 

 cember, XXVII, p. 183.) 



Leconte has discussed the question of the production of sound shadows 

 in M^ater, which, as proved by the classic experiments of Colladon in 1826 

 in the lake of Geneva, are more sharply defined than when produced in 

 air. In 1874 a series of experiments was made by his son, L. I. Leconte, 

 during the blasting ui)on Kincon rock, in the harbor of San Francisco. 

 He found that soda-water bottles i)lunged in the water about 40 feet 

 from the explosion were invariably protected when in the geometric 

 shadow of a vertical pile about a foot in diameter, while they were as 

 uniformly broken when placed on the opposite side. Stout glass tubes 

 placed horizontally showed by their fracture the lines of this shadow. 

 The author supposes, in accordance with theory, that the waves pro- 

 duced by such an exi)losion must be very short in order to produce these 

 sharp shadows. [Am. J. Sci., January, III, xxiii, p. 27 ; Phil. Mag., Feb- 

 ruary, V, XIII, p. 98; J. Phys., September, II, i, p. 420.) 



Decharme has applied the principles of attraction and repulsion ])ro- 



