1894-95.] 
Mr J. B. Hannay on Drops. 
447 
no doubt due to the surface layer containing a trace of water. The 
drops were reduced to such a size as would represent alcohol of 
94 per cent. ; whereas, on analysis, they contained only 5*62 per cent, 
of alcohol. 
Tranbe {annalen 265, 27-55), by an examination of certain 
organic alcohols and acids, concludes that the volume of the drops 
is proportional to the rise in height in the capillary tube, and the 
principal object in the present investigation was to examine this 
relationship when saline solutions are employed. The drops were 
calculated to zero rate and the experiments conducted at 20°, water 
being taken as 100 in each case : — 
Salts. 
Solution. Drop (Water 100). 
Capillary Constant 
(Water 100). 
KI 
Normal 101*3 
101*3 
JMgS04 
,, 103*4 
103-2 
iNa 2 S 04 
„ 100*4 
100-3 
KNOg 
„ 103-0 
102*8 
NH4CL 
4 times normal 108*1 
108-3 
From these numbers it is clear that the size of the drop is in 
close agreement with the capillary constant. 
In conclusion, then, the weight of a normal or infinitely slow drop 
is controlled by its surface tension or contractility ; while, when 
dropping in practice, it is modified by the rate of flow, by its 
gravity, the viscosity of the medium in which it drops, and by its 
rate of fall, all of which affect the life-time of the closing neck. 
