354 
Part III. — Ninth Annual Report 
The following table is that employed in converting the Fahrenheit 
readiiif^s which occasionally occur in the records, for the purpose of 
ensuring uniformity in the Report : — 
Fall. Cent. 
Fah. Cent. 
' Fill 
£ All. 
\_ I 111/. 
1 Fah. Cent. 
30-1-1 
40 
4-5 
50 
10-0 
60 
15-6 
10 
0-6 
31-0-5 
41 
5-0 
51 
10-6 
61 
16-1 
0-1 
32 0-0 
42 
5-6 
52 
11 1 
62 
16-7 
! m-2 
o-i 
33 0-6 
43 
6-1 
53 
11-7 
63 
17-2 
Ij 0-3 
34 1-1 
44 
6-7 
54 
12-2 
64 
17-8 
I 0-4 
j-0-2 
35 1-7 
45 
•7-2 
55 
12-8 
65 
18-3 
0-5 
0-3 
36 2-2 
46 
7-8 
56 
13-3 
66 
18-9 
1! 0-6 
37 2-8 
47 
8-3 
57 
13-9 
167 
19-5 
0-7 
0-4 
38 3-3 
48 
8-9 
58 
14-5 
68 
20-0 
! "0-8 
39 3-9 
49 
9-5 
59 
15-0 
69 
20-6 
I'l ^^'^ 
0-5 
At tlie four East Coast stations the specific gravity of the water is 
observed by means of hydrometers of the pattern used by the German 
observers, and made by Kiichler of Ilmenau. The set supplied consists 
of five instruments, graduated to read specific gravities at 17°'5 C, and 
ranging from 1000 to 1031. No. 1. ranges from 1024 to 1031, No. II. 
from 1018 to 1025, No. III. from 1012 to 1019, No. IV. from 1006 to 
1013, and No. Y. from 1000 to 1007. The temperature of the water is 
noted when the observation is made, so that all the results may be 
reduced to the standard temperature of 17°"5 C. for comparison. The 
resulting figures are of great value for comparison with those of the con- 
tinental observers, but require to be reduced to densities at 60° F. 
(15°-56 C), in order to be compared with the results already obtained for 
various places round the coast of Scotland. The importance of finding 
the density or specific gravity of water at a stando,rd temperature lies in 
the fact that it is a measure of the salinity, and that the amount of salt 
present in solution may be readily calculated from it. 
The relation of the specific gravities employed in this Report to the 
densities given in the 'Challenger' reports, and in my various papers on 
the physical conditions of the seas round Scotland, is sliown in the 
following summarised table : — 
Specific Gravity, 
17- 5^17-5 
(Pure Water = 1000-0). 
Density, 
(Pure Water = 1-0000). 
Salinity. 
Per cent, of total salts. 
1019-0 
1-0177 
2-12 
1019-5 
1-0182 
2-20 
1020-0 
1-0187 
2-27 
1020-5 
1-0192 
2-36 
1021-0 
1-0197 
2-48 
1021-5 
1-0202 
2-54 
1022-0 
1 -0207 
2-64 
1022-5 
1-0212 
2-74 
1023-0 
1-0217 
2-80 
1023-5 
1 -0222 
2-92 
1024-0 
1-0227 
3-00 
1024-5 
1 -0232 
3-08 
1025-0 
1-0237 
3-18 
1025 -5 
1 -0242 
3-26 
1026-0 
1-0247 
3-34 
1026-5 
1 -0252 
3-44 
1026-8 
1-0260 
3-50 
To save space in the Tables the figures 10 are not printed ; specific gravities 12-5 
and 26-8, for example, are to be read 1012-5 and 1026-8, pure distilled water at 17° -5 C. 
being taken as 1000-0. 
