SURFACE-TENSION OF WATER BY THE METHOD OF JET VIBRATION. 



313 



have not been introduced, as they were in this case very small ; thus the correction 

 for the decreasing of the wave -amplitudes would become completely imperceptible on 

 account of the small value of the amplitudes. Besides, the very small decrease of the 

 utmost differences corresponds to the one to be expected on account of the curvature 

 of the jet. 



We see that the wave-lengths are very constant, and that the jet at the place in 

 question must have executed exceedingly pure vibrations, because only a small 

 deviation from pure harmonic vibrations must involve considerable irregularities of 

 the differences between the readings. 



The other experiments carried out show results very similar to those described 

 here. It may be remarked that, a priori, we could expect exceedingly pure 

 vibrations of the jets from all the four tubes. The circumstance that the regular 

 variation of the differences between the readings commenced directly past the orifice 

 (see the table on p. 310) shows that already at this point we had to do with what was 

 very nearly a single vibration only, and, as mentioned on p. 300, the vibrations of the 

 jet must be much purer at a considerable distance from the orifice than close to it. 



The table below contains the result of all the experiments carried out. The surface- 

 tension is calculated according to the following equation (see p. 297) : 



2 



We see that the mutual agreement between the single determinations is very good 

 (the greatest deviation from the mean value being about 0'35 per cent.). 



It may be remarked that in the values found for T 12 no indication of a distinct 

 VOL. ccix. A. 2 s 



