98 



Viscosity of Calcium Chloride Solutions. 



The curve connecting concentration and viscosity was 

 found to be not parallel to the corresponding curve of 

 Tucker's values at 16°* 7 7 C, as had been expected, and so 

 another series of measurements was made at 20° C. in order 



05 





1 



• •• 1/fiLUES AT /6 ? 77C 

 xxx Tuckers values /?r /6°77 

 ooo Present Author's i/aiues. 



to f 





y*/ 



300 



Concentration /ngrms. pet? litre ofsolut/on. ■ 



to determine the temperature coefficient for a small range, 

 viz. 5° G. The curve drawn from the last set of numbers is 

 parallel to that for 15° C, and cuts the curve of Tucker's 

 values at a high concentration. A few determinations made 

 at 16 0, 77 C, however, seem to indicate that with the apparatus 

 used another parallel curve would be obtained at that 

 temperature. 



An important difference between the two forms of appa- 

 ratus is the length of the capillary tube. The formula 

 employed to calculate the viscosity in either case takes no 

 account of the end effect, but applies rigorously only in the 

 case wheie the stream-lines are parallel to the walls of the 

 tube. For a long tube, therefore, the ratio of the amount of 

 viscous work done at the ends of the tube where the stream- 

 lines are not parallel to that done in passing along the tube 

 will be much less than is the case for a short tube, and 

 the unknown error arising from this will be more nearly 

 negligible. It will be noticed that the tube used in these 



