132 Proceedings of Royal Society of Edinburgh. [sess. 
condition in this respect is well shown in the percentage column of 
Table II. The actual state of the mud when put up in the sample 
bottle on board depends on so many fortuitous circumstances that no 
physical importance must be attached to the figures in this Table. In 
order to bring all the muds, as far as possible, into a similar condition, 
they were heated in the water-bath until they ceased to lose weight. 
It was necessary, therefore, to determine their weights, and they 
have accordingly been tabulated, and will give roughly an idea of 
the difference between a wet mud and a dry one. 
Table II. Preparation of Substance for Analysis. — About half of 
the sample was placed in a tared porcelain basin and dried in the 
water-bath till it was in a fit form for handling. It was then 
weighed, and the loss of weight called water. 
Table II. — Preparation of Samples for Analysis , by Drying on the 
Water-Batli. 
No. of 
Sample. 
Weight of 
Mud taken 
(grammes). 
Weight of 
Mud dry 
(grammes). 
Loss 
(grammes). 
Per cent, 
of Loss. 
a 
b 
c=a-b 
a. 1 
© | 
° 
1 ^ * * 1 
31 
28-4 
19*3 
9-1 
32-04 
32 
23-8 
18-15 
5-65 
23-71 
35 
22'9 
15-3 
7-6 
33-18 j 
36 
23-0 
16*4 
6-6 
28-69 
39 
14-7 
11-7 
3-0 
20-40 
41 
26-3 
16-9 
9-4 
35-73 
43 
29-5 
20-0 
9-5 
32-20 
45 
25-1 
20-2 
4-9 
19-52 
46 
19*9 
16-1 
3-8 
19-09 
64 
24'6 
19-7 
4-9 
19-91 
65 
38*5 
27-3 
11-2 
29-09 
86 
25-4 
19-2 
6-2 
24-41 
87 
25-4 
20-7 
4-7 
18-50 
88 
29*5 
19-8 
9-7 
33-25 
89 
22-0 
16-9 
5-1 
23-18 
The dried portion was broken up in an agate mortar, and pre- 
served in a well-stoppered bottle. Sufficient quantities of each 
sample were thus prepared in a uniform manner, and the bottles in 
which they were preserved were carefully weighed and kept under 
a bell-jar. In this way any alteration in the substance is at once 
detected. If this precaution be not taken it is necessary, in dealing 
with substances which are more or less hygroscopic, to weigh out at 
