ane ees | ee ee 
E., Loomis on vibrating Water-falls. 363 
Serves merely as a load, to retard the velocity of these vibrations. 
The column of air behind the sheet of water at South Natick, is 
of such dimensions that it should make one vibration in about 
one-tenth of a second. When the depth of water is 5 inches, 
the observed time of vibration is 0088 greater than the com- 
puted time of an air vibration; but with a depth of 10 inches 
the observed time is 0°-114 greater than the computed time. 
hen an elastic string is loaded, the time of one vibration 
varies as the square root of the load. At South Natick, when 
the depth of water increases from 5 to 10 inches, the increase 
in the time of a vibration seems to be even more rapid than the | 
crease in the depth of water. 
e i 
Segments, the time of an air vibration is 0480, while the ob- 
served time is 0s:272 greater than this. 
than this. If we su ive vibrating segments, the time of 
an air vibration is 0186, while the observed time is 08050 
r than this. If we suppose six vibrating segments, the 
Am. Jour. Sct.—Szconp Series, VoL. XXXVI, No. 108.—Nov., 1863. 
47 
