364 MR. P. 0. PEDERSEN ON THE SURFACE-TENSION OF LIQUIDS 



gations on such jets with an exactness that hitherto has been difficult or impossible 



to reach. 



I will mention only very briefly some measurements of the influence of the pressure 

 on the sectional area of a jet, keeping myself within the limits where the question is 

 of interest for this investigation. The measurements comprise two circular apertures, 

 No. 1 with diameter T514 mm. and No. 2 with diameter 0'8043 mm., both arranged 

 as shown in fig. 10, where B is the perforated plate. For these I have determined 

 the sectional area of water jets for heads between 50 and 100 cm. The results are 

 shown in fig. 8, where the value a-b corresponds to aperture No. 1 and c-d to 



1,4 

 1,2 

 1,0 

 0,8 

 0,6 

 0,4 

 0,2 



c- 



10 20 30 40 50 60 70 80 90 100 cm. H. 



Fig. 8. 



No. 2. The values measured are shown by a cross ; it can be seen that they very 

 nearly fall on the straight lines a-b and c-d. 



For aperture No. 1 the sectional area decreases 4'98 per cent., while the head 

 increases from 50-100 cm. 



