102 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



is quite sensitive. By arranging two such jets, and connect- 

 ing the gas-tubes with a horizontal tube in which is a drop 

 of water, any difference of pressure is readily shown; light- 

 ing one jet causes motion towards the other side, as also 

 does shortening the flame by noise. 



Barrett has given in Nature a description of a flame ex- 

 tremely sensitive to entirely inaudible sounds. The flame 

 came from an ordinary steatite burner, having an aperture 

 of 0.04 inch in diameter, the gas being under a pressure of 

 ten inches of water. This flame, which was two feet high, 

 fell fully sixteen inches at every inaudible puff of a Galton 

 whistle, and this even at the distance of fifty feet from the 

 instrument. 



A beautiful acoustic experiment by Tylor has been de- 

 scribed in Nature^ in which atmospheric vibrations are re- 

 ceived on a soap film instead of a membrane. The end of a 

 lamp-chimney is dipped into the ordinary bubble solution, 

 and a film is formed over the opening. On singing near the 

 open end, the series of forms belonging to the various notes 

 become plainly visible in the film, and on reflecting the cal- 

 cium light to a screen by the film, the figures come out on 

 the screen with great beauty. If the solution be thin, the 

 film is almost devoid of color; but if thick, a gorgeous 

 scenic effect is produced by the masses of prismatic color 

 whirled hither and thither by the musical vibrations. 



Jeannel has observed that the radiometer is influenced by 

 sound vibrations. In a dim light, when three radiometers 

 were placed on the sounding-board of a parlor organ, all 

 moved, two in the direction produced by light, the other in 

 the opposite. He explains the result by the transmission of 

 the vibrations mechanically to the vanes. 



HEAT. 

 1. Thermometry. 

 Herve Mangon has contrived a new registering thermom- 

 eter of extreme sensibility and delicacy. A capillary tube 

 containing mercury is bent to a narrow rectangle at one 

 end, and is drawn out to a fine point at the other. This 

 thermometer is inverted, and the point dips into a small dish 

 of mercury on the scale-pan of a delicate balance. On the 



