(b. 
26 
sodium chloride in a known volume of distilled water. 
The sodium chloride was obtained from the ordinary 
crude salt by precipitation from a strong aqueous 
solution by means of hydrochloric acid. The precipi- 
tate was filtered, dried, and finally fused. The actual 
strength of the salt solution prepared was nearly 3p, 
and this could then be diluted as required. 
The ammonium sulphocyanide solution was prepared 
by dissolving the pure salt in water in such proportions 
as to make it approximately decinormal. Its actual 
strength was not determined as it was titrated against 
the silver nitrate solution only to find the ratio between 
their strengths. 
Saturated solutions of the two indicators—potassium 
chromate and iron alum—were employed, one drop 
being sufficient for each titration. 
)—VonHarp’s MeruHop. 
A sample of sea water (about 10°0 ce.) was titrated 
as a preliminary, in order to find about the amount of 
silver solution required. 
The accurate determinations were then done in the 
following way :— 
10cc. of the sea water was measured from a pipette 
into a beaker, and mixed with a little distilled water. 
About 2ce. more silver solution was then added than 
the preliminary examination had shown to be neces- 
sary. The mixture was thoroughly shaken and allowed 
to settle, and the nearly clear supernatent liquid was 
filtered. The residue in the beaker was twice washed 
with distilled water, and the washings were mixed with 
the filtrate after they themselves had also been filtered. 
All the excess of silver was now found to be in the 
