480 
Proceedings of the Boyal Society 
Alkalinity. 
We intended to observe the alkalinity of numerous samples of 
sea and river water, and for this purpose we had procured the 
necessary standard solutions from Professor Dittmar. Practical 
difficulties prevented the carrying out of this plan, and few deter- 
minations were made. It is advisable to mention the results 
obtained (Table III.), meagre though they be. The only conclu- 
sions we can draw from the consideration of them, and these we 
present with some diffidence, are — 
1. The alkalinity (which is a measure of the potential carbonate 
of lime present) is less, for waters of the same density, than in the 
Firth of Forth. 
2. In water taken on different occasions from the same position 
the alkalinity is not proportional to the density, but appears to be 
liable to variation. 
3. There are indications that the alkalinity of the water in 
Spey Bay is, for the same density, greater to the east of the river 
mouth — that is, in the direction of the fresh current. This may be 
due to the carbonate of lime carried down in solution by the fresh 
water. 
4. There are no distinct indications of a uniform change of 
alkalinity with depth, although surface water is more alkaline than 
that at the bottom, even when the density of the former is less. 
In Table III. alkalinity is represented by the number of milli- 
grammes of carbonic acid (C0 2 ) existing in normal carbonates 
(R"C0 3 ) in one litre of water. Thus, if a sample had alkalinity 
50‘00, it contained 50 milligrammes of carbonic acid in combina- 
tion with lime or with some other base, equivalent to 113’7 milli- 
grammes of normal calcium carbonate (CaC0 3 ). 
Temperature of the Water. 
The temperature of the water in the bay was lower than in the 
river. The water at the bottom was colder than at the surface, the 
difference being about 3°, where the depth was 10 fathoms. Full 
particulars of the observations are given under VIII., IXa., X., 
XI., and of those along the shore under XII., XIII., XIV. 
The temperature of the river was observed once or twice daily 
