INVESTIGATED BY IMF. METHOD OF JET VIBRATION. ;15H 



1 millimetre. Several inthienees result fn>m this which with a greater diameter of jet 

 have only secondary importance, hut lien- take a prominent part. I shall quite super- 

 ficially treat these influences here, as I hope later to have an opportunity to give a 

 more exhaustive account >(' this suhject. 



In Tonuii 1:1.1.1 's formula H indicates the pressure measured from the jet to the 

 fluid's .surface; but this in reality must he reduced by the pressure produced by the 

 surface-tension in the interior of the jet. Let </ cm. lie the diameter of the jet, p t In- 

 tensity, and T dyne/cm, the surface-tension, then will the pressure produced by the 

 surface-tension correspond to a head of liquid, the height of which, h cm., is 



determined hv 



2T 



... : ......... (I). 



If we take, for example, for water d = O'l cm., p = 1, T = 73*5 dyne/cm., we have 

 li = circa 1*5 cm. As can be seen, it is a correction which is not quite infinitesimal, 

 though but little attention has been given to it. C. CHRISTIANSEN* is probably the 

 first who has commenced the investigation with special regard to the conditions under 

 discussion. Some experiments of M. IsARNt also confirm the alx>ve view. He 

 determined the time that elapsed for 141 cm :t . of fluid to run through a circular hole 

 of a diameter of 0'8 mm. with the pressure varying from 11 '8 cm. to 9'0 cm. and 



for water 290 seconds, 

 alcohol 270 



These two measurements will now be calculated with reference to the correction 

 mentioned before (l), it being supposed that the diameter of the jet in both instances 

 was d = 0'07 cm. 



For water we take p = 1,1 = 73'5 dyne/cm. ; for alcohol we take p = 0'8, T = 22'0 

 dyne/cm. 



In accordance with this the above correction will be for water h = 2'14 cm., for 

 alcohol h = 0'80 cm. 



The effective pressure will according to this be 



For water H = (v/ll-8-2'14 + v/9'0-2-14)' = 8 "20 cm. 



alcohol H = | (v/H '8-0-80 + s/9-0-0'80) s = 9'53 cm. 



The total discharge will be 



0-07* 



For water IT . - - s/2'981 . 8-2 . 290 = 141 -3 cm 3 . 

 4 



0-07* 



alcohol ir . v/2'981 . 9'53 . 270 = 141'8 cm 3 . 



* C. CunisTiANSEX, 'Overs. \ "i.lonsk. Sclsk. Forh.,' p. 65, 1901 ; 'Ann. d. Phys.,' 5, p. 436, 1901. 

 t M. ISAIIX, ' Journ. d. 1'hys.' (1), 4, p. 167, 1875. 

 VOL. CCVII. A. 2 Z 



