Chemistry and Physics. 253 
merely shaking up — silica in the pipe—be made to give different tones, 
the pitch of which i s easily ascertained by the ear, and the length of 
whose waves is found to coincide admirably with rs calculation based 
upon the first determination and the interval—or the veloc ocity of sound 
and the number of vibrations. The known methods of Blosk ts oe 
and others, for representing the vibrations of the air in organ pipes a 
ext deficient Kundt’s method is as complete as it is simple. 
it shows more than anticipated. If repeated by means of a verti- 
cal sine with a gas-flame in place of the silica, this flame shows a cor- 
tube. From this and other facts Dr. Kundt concludes that the rippling 
me probabl 
one produced, and whose wave-len gth is measured by twice the cia 
tween two consecutive nodal areas. 
For farther detail, and many other interesting results, we must refer to 
the paper of Kundt in Poggendorff’s Annalen, pad: CXxvili, 337-355 
and 496. In the same volume, page 610-613, the same investigator 
gives an interesting cE for the observation of ‘ae vibratory forms of 
ae by means of reflec i 
Influence of the pirat friction of the air on the transmission of 
iene; Sreran (Acad. Vienna, April, 1866).—The analytical pore 
(1.) The velocity is greater for the tones of higher pitch; for the 
highest tones it only is one-thousandth of a millimeter [so that disper- 
sion of sound is practically impossible ?] 
(2.) The amplitudes of plane progressive waves decrease in a geomet- 
tical progression, the ratio of which is proportional to the square of the 
number of vibrations. The am mplitude is reduced to one-ninth in 1000 
Pa for 10,000 vibrations, or in 100 meters for 30,000 vibrations per 
x ‘In stable vibrations the merelengily cannot be greater than four 
es the mean excursion of a molecule of the air (as assumed in Kré- 
gases) 
: “) The amplitudes in stable waves decrease in geometrical progres: 
sion of the time, the ratio gid proportional to the square of the num- 
Am, Jour, ionaechisun Sexirs, Vou. XLIII, No. rhiehcosten 
33 
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