(38 
Wanklyn &; Chapman’s Water Analysis, as were also the 
ammonium, albumenoid ammonia, and nitric acid. 
By a comparison of the above two analyses it is evident 
that between September, 1871, and September, 1874, the 
composition of the water has varied considerably, and 
though the author has not had an opportunity of seeing the 
analysis made in 1844 by Waldie, yet from Dr. Hassalls 
report, given in the above-mentioned pamphlet, it would 
seem that the results there given also vary much from those 
obtained by Waldie. The quantity of iron appears to have 
greatly diminished, while, with the exception of SiOg and 
chlorine, that of the other constituents occuring in larger 
quantities has considerably increased. A determination of 
the iron made last February gave 1575*4 parts per 1,000,000, 
though in this case the determination was not made till 
O 
after the water had been collected some days. From this 
it would seem that the iron is gradually diminishing in 
quantity. The result, however, obtained by Waldie is 
very nearly the same as that got by Hassall. 
From the analysis it will be seen that the Trefriw water 
is peculiar, as already mentioned, on account of the large 
quantity of sulphate of iron which it holds in solution; 
there being, so far as the author has been able to learn, no 
spring in the United Kingdom, and perhaps not even on 
the Continent, which contains it in anything approaching 
to tlie same amount, while there are only a few springs 
known which contain it even in a notable quantity, the 
analyses of which have been described. The water is also 
remarkable for the large quantity of sulphate of alumina 
and silicic acid which are dissolved in it, while the phos- 
phoric and nitric acids, though existing only in small 
amounts, are rather large compared with what is found in 
most other mineral waters ; on the other hand the propor- 
tion of chlorine is only small. 
The other Trefriw mineral spring was not analysed, but 
