460 



Mr. Owen Glynne Jones on 



Mass. 



Mean 

 temp. 



Time. 



Time 

 corrected 

 to 4 u -35 0. 



3 



Mass, m. 



a 



b 



c 



d 



f 



9 



h 



3 



4-30 

 432 

 4-45 

 4-28 

 4-41 

 4-48 

 423 

 4-32 

 4-40 

 4-50 



seconds. 

 111-6 

 101-4 

 116-1 

 123-1 



99-8 

 150-5 



89-75 

 1074 

 108-3 

 114-3 



seconds. 

 111-1 

 101-1 

 117-2 

 122-4 

 100-4 

 152-3 

 88-77 

 107-1 

 108-8 

 115-9 



•08401 

 •09680 

 •07751 



•07265 

 •09782 

 •05236 

 •11760 



•08876 

 •08667 

 •07885 



grm. 



•01080 



•01244 



•00996 



•00934 



•01257 



•00673 



•01512 



•01141 



•01114 



•01014 



2 =-85303 



2= -10965 



Thus 



/*4°-35 c. = 46*27. 



The value of %v?, when no corrections are made for tem- 

 perature, is found to be 



V f = -85434, 



which agrees fairly well with the above result. 



The temperature-variation of viscosity is considerable. It 

 is of practical importance in certain applications, as, for 

 example, in the use of viscous liquids for lubricating pur- 

 poses. A special piece of apparatus was used by the author 

 to investigate this variation for different liquids. 



It consists of a glass tube closed at each end, with a lateral 

 tube fixed at right angles to its middle portion and forming 

 an outlet. The vessel is filled with the liquid and a very 

 minute sphere of mercury is inserted. A thermometer passes 

 through a stopper that encloses the liquid, the bulb of the 

 thermometer reaching just up to the main tube. The vessel 

 is immersed in a copper water-bath so that the main tube is 

 vertical and the thermometer horizontal. The thermometer 

 passes out of the bath through a small stuffing-box on one 

 side. A window of glass is inserted in the opposite side of 

 the bath through which the taiotion of the mercury may be 

 observed. As soon as the mercury has fallen to one end of 

 the tube, it is reversed and the mercury allowed to fall down 

 to the other end again. 



The thermometer reads the temperature of the viscous 

 liquid at its middle, this being very nearly the mean tem- 

 perature. The bath is heated slowly to about 50° and then 



