25 
4.—SusPpENDED MatTTER. 
This was not estimated owing to the difficulty of filtering 
large volumes of water, and of weighing small amounts of 
ash. It was very abundant in the Mersey water at low 
tide, but not nearly so abundant at high tide. There 
was quite an appreciable amount of suspended material 
in all samples off the Lancashire coast, but in the open 
sea, and round the Isle of Man, the water is practically 
clear. 
For the determination of the specific gravity and other 
characters, the sediment was allowed to settle and the 
clear water decanted off. 
5.—EstTiMATION OF THE CHLORINE. 
This was done with the greatest possible accuracy, both 
by Volhard’s method and also by titration with standard 
silver nitrate solution, using potassium chromate as 
indicator. 
The exact process by each method is given and also the 
results, for the sake of comparison. 
(a.)—PREPARATION OF SOLUTIONS. 
The silver nitrate solution was prepared by 
dissolving the pure fused salt in sufficient water to 
make about. a decinormal solution. ‘his could then 
be diluted to any desired extent. 
It was standardised by titration against the sodium 
chloride solution (which see), using potassium 
chromate as indicator, and also by Volhard’s method 
It was restandardised about once a week, in order to be 
certain as to its exact strength from time to time. 
The sodinm chloride solution was prepared by dis- 
solving an accurately determined weight of pure, dry 
