195 — 
TABLE XI. 
i 
mm. 
Water r/t. = 2”. T=22 w .9 C. r. — 7 . 1 Number of drops =20. 
Substance. 
Weight of 
20 drops. 
Mean weight of 
single drop 
Cork 
Glass 
Brass 
r 
i 
1 
L 
< 
2.4846 
2.48 18 
2.4832 
2.4789 
2.4821 
2.4877 
2.5930 
2.5985 
2.5989 
2.5949 
2.5953 
2.5900 
2.6225 
2.6229 
2.6260 
2.6295 
2.6296 
2.6116 
S- 0.12418 
> 0.12975 
0.13118 
When a liquid drops from a solid it is not always that the 
adhesion between the solid and liquid is overcome. The 
phenomenon of wetting ” implies a superiority of the adhe- 
sion between the solid and liquid over the cohesion of the li- 
quid : and in all cases where a liquid drops from a solid which 
it wets, the act of separation is a disruption of the liquid and 
not a separation of the liquid from the solid : that is, the sepa- 
ration is a failure of cohesion and not of adhesion. We arc 
not, however, on this account, justified in anticipating that 
the size of a drop is unaffected by the chemical nature of the 
solid from which it drops, even in those cases where the ad- 
hesion between the solid and liquid is greater than the cohe- 
sion of the liquid, that is, where the liquid completely wets the 
solid : because although it is the liquid which is broken, yet 
