358 



Drop-method. 1*^ series, m 1.09. 



^12 3 4 5 



t 102.7 119.7 143.3 174.3 216.9 



temp. 15.5°. 



These points do not lie exactly on a straight line. The deviation 



is very small for the first three drops; the fourth point is too 



high and the fifth deviates still more in the same direction. The 



first two drops give 



a = .135 i = 97.99. 



' As this result does not agree with the former result as regards 

 n, a further investigation of the method was made with air after 

 the completion of the observations with butane. In this case three 

 quantities of mercury were taken, each of which was used in a 

 different number of drops. 



The results were as follows -. 

 Drop-method 2"^^ series, a- 1 2 3 



m 2.11 t 49.0 54.4 62.0 temp. 19.8. 



ni 1.53 / 69.1 80.1 97.9 temp. 1-9.5. 



m 1.06 i 103.6 129.9 temp. 19.5. 



From this set the intluence of capillarity for one, two or three 



drops may also be calculated by RA^•KI^E's method. 



The first column gives a = .121 /; = 97.59 for one drop, 

 second „ „ a = .306 b = 98.31 for two drops, 



third „ ,, a = .533 b = 97.97 for tiu-ee drops. 



The capillary effect per drop thus becomes: 

 .121 .153 .178. 



it seems therefore to become greater as the number of drops 

 increases. 



The value of b is practically constant: the deviations are 0.47^ 

 and remain below the eri-ors of observation. 



In the calculation by the drop-method (combination of the results 

 in the same row) the third point appears to deviate downwards 

 this time. 



The first row gives for .t=l and .i=2; a = .192 Z/=94.1 for m=1.1i 

 „second,, „ „ ^z = .185 6=93.1 „ 1.53 



„ third ., „ „ . a = .17d 6=91.6 „ 1.06. 



The deviation from Rankine's method of calculation is also in 

 the opposite direction. The differences between the constants b are 

 again much smaller than those between the as. 



The conflicting results of the two series of observations make it 



