1906-7.] On the Application of a Differential Densimeter. 223 
requisite flexibility, and any damage it may suffer can be at once repaired 
by the substitution of a duplicate for the broken part. The cisterns can 
be emptied, rinsed, and drained quite easily without detaching them from 
the vertical tubes. 
In order that the instrument might be capable of rendering the fullest 
service on board ship, it would probably be necessary to suspend it in 
gimbals. The plane containing the knife-edges of the gimbals should be as 
near as may be convenient to the horizontal plane passing through the 
axis of the reading microscope. It would also be necessary to load the 
lowest extremity with, say, a moderately large block of lead. 
The instrument, having been calibrated in the manner previously de- 
scribed, was used to measure the densities of the remaining sixty samples 
of sea- water. 
In Table YI. are set forth the values obtained with (a) the pyknometer 
at 18 ° C., and (b) the densimeter, with their differences ; the corresponding 
amounts of combined chlorine per litre of water are also tabulated. 
Table VI. — Densities, etc., of Waters collected between Marseilles and 
Cape Finisterre, October 1905. 
No. of Water. 
a 18 by 
• the 
pykno- 
meter. 
A 18 by 
the den- 
simeter. 
Differ- 
ences. 
Grams 
of Cl 
per 
litre. 
Time. 
Temp. 
Position of Ship. 
31. 
32. 
33. 
34. 
35. 
36. 
37. 
38. 
39. 
40. 
41. 
42. 
43. 
44. 
45. 
46. 
47. 
48. 
49. 
50. 
51. 
52. 
53. 
54. 
55. 
56. 
1-02919 
10 
45 
1-03050 
•02889 
•03133 
•02873 
821 
819 
800 
•02933 
•02821 
•02773 
73 
73 
79 
72 
74 
72 
73 
68 
67 
74 
70 
68 
72 
1-02914 
02 
34 
1-03044 
•02885 
•03123 
•02870 
817 
809 
799 
930 
822 
774 
773 
766 
Insuffici 
1-02775 
79 
83 
81 
72 
71 
77 
75 
71 
72 
- -00005 
8 
11 
6 
4 
10 
3 
4 
10 
1 
3 
+ 1 
+ 1 
± 0 
7 
ent water. 
+ -00003 
+ 5 
+ 11 
+ 8 
-1- 4 
+ 4 
+ 3 
+ 5 
+ 3 
± 0 
21- 710 
•639 
•921 
22- 663 
21-533 
23333 
21-374 
20- 933 
•933 
•792 
21- 745 
20-968 
•615 
•580 
•580 
•580 
•580 
•615 
•615 
•615 
•615 
•615 
•615 
•615 
•580 
•615 
§ [ 8 a.m. 
V 1 Noon 
§1 Jp.nL 
rtf 8 " 
<g 1 Midnight 
f 4 a.m. 
8 ii 
O ! Noon 
rtf 1 4 p.m. 
8 m 
l Midnight 
r 4 a.m. 
8.30 m 
8.45 u 
9.0 u 
9.15 n 
9.30 .. 
■g 9.45 m 
°<10.0 M 
£ 10.15 m 
^ 10.30 n 
10.45 m 
11.0 .i 
11.15 M 
11.30 m 
11.45 m 
62° 
64° 
63° 
64° 
64° 
63° 
70° 
63° 
66° 
64° 
63° 
60° 
64° 
63° 
62° 
62° 
63° 
66° 
67° 
66° 
66° 
66° 
67° 
66° 
66° 
68° 
6.44 a.m., 5 miles off C. Palos. 
j 1.41 p.m., 5| miles off C. Gata. 
\ 3.52 m 9" m C. Sabinal. 
f 5.35 a.m., 1 mile off C. Enropa. 
\ 8.13 M off Carnero Light. 
9.21 a.m., 2 miles off Tarifa. 
1 10.40 a.m., j35° 58' N. lat. 
\ course altered ( 5° 52' W. long. 
11.24 a.m., off Trafalgar. 
