362 Proceedings of Royal Society of Edinburgh. [sess. 
It will be observed that the temperature coefficients of the Ply- 
mouth waters distinctly differ from those of the waters fromSandown. 
Determinations of the amount of chlorine per litre of the water 
were made for certain of the above-named samples; these were 
effected (1) in the usual manner with standard silver nitrate 
solution and potassium chromate as indicator, and (2) according 
to the method devised by Gay-Lussac. The individual results 
Table III. 
Plymouth 
Water. 
C?24* 
P24- 
1 
P'24 
ax 10 5 . 
0 x 10 7 . 
Chlorine 
per litre. 
Natural 
No. 1 
„ 2 
„ 3 
„ 4 
„ 5 
,, 6 
„ 7 
1-02676 
71 
67 
64 
61 
57 
1-02543 
1-02424 
18*4461 ohms 
•4645 „ 
*4979 „ 
•5052 „ 
•5155 ,, 
•5523 „ 
19*2608 ,, 
20‘0775 „ 
*054212 mho 
•054158 „ 
•054060 „ 
•054039 ,, 
•054009 ,, 
•053902 ,, 
•051919 „ 
•049807 „ 
-2470 
- 2518 
-2551 
-2428 
+ 2810 
+ 2970 
+ 3082 
+ 2694 
20*4297 grms. 
20-3714 „ 
19-4465 ,, 
18-5162 „ 
Cardigan ) 
Bay V 
Water. ) 
1-02491 
19-6037 „ 
0-51011 „ 
/ The specific \ 
resistance of 
this water was I 
4 measured at r 
24° C. a and /3 
1 were not deter- 1 
' mined. 
18-9336 „ 
were almost identical, and their mean values are given in the 
last column of the immediately preceding table. 
An attempt to discover some definite and simple relationship 
between the electric conductivity of a water and the amount of 
chlorine contained in it met with no greater success than that 
which attended the effort to correlate the conductivities and 
relative densities. 
It is a matter for regret that there should be no simple pro- 
portionality between the electric conductivities on the one hand, 
and the relative densities or total amount of chlorine present on 
the other; and the more so on account of the fact that the 
electrical method has proved to be so much more sensitive than 
any of those other methods which are at present almost exclusively 
used in sea-water determinations. 
(. Issued separately January 24, 1903.) 
