— 181 
The column of the relative sizes of single drops (which is 
got by dividing the mean weights by the respective specific 
gravities) shows that, under like conditions, a drop of water is 
larger than a drop of solution of chloride of calcium of any 
strength whatever. The comparatively small quantity of so- 
lid matter in S /128 causes the drop to diminish about l /g of its 
volume. Me must bear in mind that the successive incre- 
ments of solid matter affects the size of the drop in several 
ways. By affecting the cohesion of the water : by asserting 
its own cohesion j by its superiority in weight determining a 
fall of a drop comparatively sooner, and in this case by the che- 
mical affinity of the solid to the liquid, which may be saltatory 
according to the possible hydrates of chloride of calcium. It 
is seen that these various influences cause an irregularity in 
the diminution of the size of the drop as it acquires more so- 
lid matter. In fact, it is only when the liquid has the great 
strength of S/s that the diminution in drop size becomes, con- 
tinuous. On account of the chemical union which takes place 
on dissolving Ca Cl in water I have not given the absolute 
strengths of the various solutions. To see how much of the 
intermediate irregularity is due to the existence of chemical 
union between the two bodies of which the liquid is compos- 
ed, we may next take nitrate of potash which as far as is 
known does not combine with ■water at all. 
Solutions of nitrate of potash were made of the following 
strengths by weight : — 
.22 of water to 1 of nitrate of potash. 
•)9 
) * 
9 
yy 
90 
y y 
3 
yy 
yy 
y ) 
90 
} y 
4 
y y 
yy 
22 
22 
22 
22 
yy 
y y 
9 
(j 
8 
.) f 
y y 
yy 
yy 
yy 
yy 
yy 
These were made to drop from the ivory sphere (Fig. HI) 
