888 



ME. P. 0. PEDERSEN ON THE SURFACE-TENSION OF LIQUIDS 



methods, as the smallness of the amplitudes renders the direct measurement 

 impossible. 



With due consideration of the above remarks, Lord RAYLEIGH'S method is a very 

 good one, and is highly deserving of use in the future on account of its great 

 fundamental advantages. 



With regard to the results obtained in this investigation, the author desires to call 

 attention to the remarkable discrepancies between his results and those of GRUNMACH, 

 who used the method of capillary ripples^with renewal of the surface (see p. 343 

 above). It was to be expected that the difference between the two sets of values 

 should be small, and further, that GRUNMACH'S values should be intermediate between 

 the author's values and those obtained by the capillary-tube method. But that is 

 very far from being the case : the differences are rather great, and of a sign opposite 

 to that expected. 



In further application of this method the author would propose to use apertures 

 with amplitudes between 4'0 and 0'5 ; for instance, the following set : 



8 = 4-0, 8 = 2-0, 8 = 1-0, and 8 = 0'5. 



TABLE XVIII. 



Table XVIII. contains a few results compiled from the above measurements, 

 illustrating the relation between the cross-section of the jet (A) and the coefficient 

 of viscosity (/u,). The table is calculated for orifice III. ; H is the effective head. 

 The table shows that the cross-section increases with the viscosity. 



