192 
THE VOYAGE OF H.M.S. CHALLENGER. 
The nitrogen contained in a litre of surface water always tends to assume the value 
1000 Xfij, corresponding to the prevailing temperature t 0 . This suggested to me the 
calculation of the following Table XVIII., which reads as follows : — 
Column I. gives the number of the water analysed. 
Column II. its natural temperature, t Q . 
Column III. as t the one of the values 0°, 5°, 10°, &c., which is nearest to t 0 . 
Column IV. the volume of nitrogen (in c.c. reduced to 0° and 760 mm.) found in 1 
litre of the water at t 0) corrected up or down to t by means of Table IX., page 175, on the 
assumption that, for the same interval of temperature, A (the volume of nitrogen per 
litre) is the same as the A (1000Xn 2 ) of Table IX. 
Table XVIII. 
The Quantity of Nitrogen in Surface- Waters reduced to certain 
fixed Temperatures. 
I. 
| No. of 
i Water. 
IL 
III. 
t. 
IV. 
Nitrogen 
found at t 0 
degrees re- 
duced to t 
degrees. 
V. 
Nitrogen 
calculated 
for t degrees. 
I. 
No. of 
Water. 
II. 
• 
III. 
t. 
IV. 
Nitrogen 
found at t 0 
degrees re- 
duced to t 
degrees. 
V. 
N itrogen 
calculated, 
for t degrees. 
396 
0*4 
o 
0 
13-88 
15-60 
1510 
2 To 
o 
20 
9-96 
10-41 
389 
- 1*7 
0 
1411 
15-60 
1508 
200 
20 
10-08 
10-41 
386 
- 0-7 
0 
1504 
15-60 
1699 
20-5 
20 
10-34 
10-41 
417 
7 2 
ft 
13-68 
13-86 
977 
21-7 
20 
10-38 
10-41 
1272 
11*8 
10 
1014 
12-47 
1683 
22-5 
20 
10-65 
10-41 
1271 
11-9 
10 
11-97 
12-47 
682 
26-9 
25 
8-22 
9-62 
1424 
94 
10 
12-71 
12-47 
990 
23-9 
25 
8-54 
9-62 
1987 
125 
10 
12-74 
12-47 
1187 
22-9 
25 
8-72 
9-62 
1378 
12-7 
15 
10-26 
11-34 
1004 
24-4 
25 
8-87 
9-62 
1374 
14-2 
1 ft 
10-35 
11-34 
528 
25-5 
25 
8-90 
9-62 
1462 
14-2 
1 ft 
1056 
11-34 
817 
25-8 
25 
9-09 
9-62 
137 ft 
13-9 
15 
10-91 
11-34 
581 
26-4 
25 
9-11 
9-62 
486 
140 
1 ft 
10-92 
11-34 
557 
26-7 
25 
913 
9-62 
471 
lft -6 
15 
11-34 
11-34 
1003 
24-0 
25 
915 
9-62 
1314 
13-6 
1 ft 
11-44 
11-34 
1176 
24-2 
25 
9-20 
9-62 
| 1364 
165 
1 ft 
11-54 
11-34 
1687 
22-8 
25 
9-30 
9-62 
1367 
lft-ft 
15 
11-64 
11-34 
532 
25 1 
25 
9-48 
9-62 
1342 
16-9 
1 ft 
11-70 
11-34 
1590 
25-1 
25 
9-53 
9-62 
1366 
lft-ft 
15 
11-90 
11-34 
1573 
25-1 
25 
10-03 
9 - G 2 
1301 
14-7 
1 ft 
12-44 
11-34 
572 
250 
25 
1003 
9-62 
1212 
18-9 
20 
8-34 
10-41 
761 
28-9 
30 
8-13 
8-94 
926 
219 
20 
853 
10-41 
722 
28-6 
30 
8-33 
8-94 
826 
21-8 
20 
9-39 
10-41 
602 
27-9 
30 
8-51 
8-94 
1211 
19-5 
20 
9-71 
10-41 
700 
27-8 
30 
8-58 
8-94 
512 
21*9 
20 
9-71 
10-41 
759 
28-6 
30 
8-95 
8-94 
836 
20-8 
20 
9-86 
10-41 
638 
29-4 
30 
8-97 
8-94 
1514 
18-4 
20 
9 89 
10-41 
1629 
27-9 
30 
9-08 
8-94 
910 
21-7 
20 
9-99 
10-41 
612 
28-3 
30 
9-47 
8-94 
