THE VOYAGE OF H.M.S. CHALLENGER. 
232 
methods, hv which the double determination of the carbonic acid and the carbonate is 
made in one operation. 
I hiring the cruise I frequently tested the freshly collected sea- water, and I always 
found it to have a slightly alkaline reaction. On a number of occasions I determined 
the amount of hydrochloric acid required to neutralise it in the cold, as indicated by 
the usual rosolic acid solution. This is not to be confounded with Tornpe’s alkalinity 
t -st, which is conducted at a boiling temperature and has a great value as a quantitative 
method. My object was more to accentuate the fact that the water is alkaline in its 
natural state than to show how alkaline it is, for I noticed that after neutralisation 
the water became alkaline again on standing. 
The few determinations of “ organic carbon ” by means of permanganate of potash 
(p. 122) were experimental, and were entered in my journal in course. I was, however, 
.so dissatisfied with the experiments that I soon gave them up, and I attach no value 
to the results. 
