Joty—Some Sedimentation Experiments and Theorves. 396 
TABLE II. 
Rave or Compactinc. — INFLUENCE or VALENCY. 
5 Grammes Slate Powder in 12 c.cs. Liquid. 
Minutes Depression of Surface of Sediment 
from Com- peeiies Appearance of Liquid 
| HaSneomeny . . above Sediment. 
of First Second Third | | 
Settlement. | Settlement. | Settlement. | Settlement. | 
10 1:5 1:2 iol 
MeCl, | 20 2-9 25 2:3 
0-01 gramme 30 4:6 3°8 3°6 Nearly limpid. 
equivalents. | 40 5:7 5:2, 4:8 
| 50 59 5°6 55 
10 1:3 1:2 11 
MgCl, | 20 2:8 2-1 2-1 More translucent 
0:005 gramme 30 4:1 3:1 3°1 than paraffin 
equivalents. | 40 5°6 4-1 4-1 Wax. 
50 6:1 5'3 5:0 
10 1:3 1:2 101 
NaCl 20 2-5 2-1 2-0 : | 
0-01 gramme 30 3-9 3-1 3-0 afte en 
equivalents. 40 5:1 4-1 3°9 Bebe “ai 
50 6:3 5:2 4:8 
10 1:3 1:4(2)) (2) 
NaCl 20 2°5 24 | (2?) Very muddy, | 
0:005 gramme 30 38 By a (?) translucency of | 
equivalents. 40 4:8 4-3 | (2) tallow. 
- 60 61 |) 5:3 | (2) 
| | 
The following experiments, Table III., show the difference in behaviour for 
sea water and fresh water; the latter obtained from the city supply. Tour 
grammes of slate were used and 10 e.cs. of liquid. The numbers are the 
depression of the surface of sediment in c.ms. below meniscus of liquid. It will 
be seen that in the fresh water suspension no surface was discoverable. 
TABLE III. 
Minutes elapsed. Sea Water. Fresh Water. 
5) 2°6 2 
10 4:7 2 
15 5:9 2 
20 6:3 2 
25 6°5 2 
110 6:8 2? 
During the experiment a dark layer appeared rising in the bottom of the 
fresh water suspension due to the coarser particles collecting below. 
In all these experiments care was taken to render the experiments strictly 
comparative by mounting the tubes in groups close together upon the one stand 
