394 Mr. T. Proctor Hall on New Methods of 



Eliminating x by the principle of proportion, 



T = 



m — n 



n — r 



also 



2(a-b) 2(a-c) 2(b-c)' 



from which the following values are obtained : — 



T (gram). 



x (centim.). 



•074089 

 •074088 

 •074092 



•0074 

 •0073 

 •0073 



Mean ... -074090 



•0073 



The value of x, for rigid frames, depends almost wholly 

 upon the thickness of the vertical sides n n. If the frame be 

 so slender as to allow these sides to approach each other 

 sensibly under the tension of the film, the value of x will be 

 increased. The following results were obtained in the course 

 of my work : — 



Widths of 



frames, 

 in centim. 



Thickness 



of sides 

 (centim.). 



Liquid. 



T 



(dynes). 



X 



(centim.). 



Notes. 



523 

 2-03 

 020 



•025 to 

 •029 



Water. 



72 6 



•0073 



Frames 

 nearly 

 rigid. 



11-76 

 0-92 



•038 to 

 •040 



- 



72-8 



•0073 



Eigid. 



11-22 

 1-06 



•076 to 

 •080 



j> 



73-4 



•0191 



» 



» 



J? 



50 per cent, 

 alcohol. 



30-3 



•0186 



» 



11-88 

 0-96 



•028 to 

 •033 



Water. 



72-9 



5» 



•0136 

 •0139 



Slender. 



The capillary correction for a rigid frame 10 centim. wide, 

 whose vertical sides are half a millimetre thick, does not 

 exceed 1 part in 1000. 



