C. GENERAL PHYSICS. 



195 



the motion lessens, only one set of lines perish, and the sur- 

 face is covered with rectilinear waves perpendicular to one 

 of the bases. Elliptical vessels give figures of exceeding 

 beautv, the lines having reference to the two axes of the el- 

 lipse. The author calls attention to the general character of 

 these wave-surfaces. In the basin of a fountain, in the waves 

 of the sea, these forms are recognized ; even in the sand on 

 the bottom of the sea they can be traced. Certain lines thus 

 made gave on measurement 2.6 vibrations per second. They 

 may be seen 100 meters from the beach, and at a depth of 

 eight to ten meters. So, out of the water, the sand on the 

 beach was found to have taken these forms : thus suo'frest- 

 ing that the air itself was capable of similar vibration. So 

 also clouds are arranged often in parallel bands, being then 

 considered a precursor of fine weather. Even in geology, the 

 author regards certain regular and equidistant foldings of 

 rocks as evidence of analogous vibrations. The ventral seg- 

 ments of a liquid vein, M. Barthelemy thinks, are produced 

 by the vibration of the liquid mass upon which it falls re- 

 acting uj)on it. And he makes an ingenious application of 

 these facts to account for the phenomena of stratification pro- 

 duced by electric discharges in rarefied media. Ann. Chun. 

 JPhys.,Y., January, 1874 ; Amer. Jour. Science, June, 1874. 



AIR-PRESSURE REQUIRED TO SOUND VARIOUS WIND INSTRU- 

 MENTS. 



Dr. W. II. Stone has recently measured the air-pressure re- 

 quired to sound various wind instruments, by introducing 

 into the mouth of the performer a small glass tube connect- 

 ed with a water-pressure gauge. He thus ascertained that 

 when the musicians sounded "mezzo-forte" on the following 

 instruments, air-pressures were produced in the gauge as giv- 

 en below opposite the respective instruments : 



Oboe 



Clarionet. . 



Bassoon 



Horn 



Cornet 



Trumpet 



Euphonium 

 Bombardon 



LOWER NOTES. IHCI1EST NOTES. 



