244 A. A. RAMSAY. 
These higher oxidised products may be removed, and con- 
cordant results obtained, if the solution be reduced with a 
little potassium iodide, and the excess of iodine removed 
by boiling. With this alteration, I find the method gives 
excellent results. 
For the determination of the total lime present I now 
prefer to decompose the sulphides of calcium with N/10 
iodine solution, filter off the precipitate of sulphur and 
determine lime in the filtrate as usual by ammonium oxalate. 
The method gives excellent results and obviates the 
necessity of doing a blank determination of lime in the 
sodium peroxide used. 
The results of these analyses are given in Table I in (a) 
grams per 100 cc. and (b) pounds per 50 gallons. The 
‘‘calculated lime”’ is the lime calculated as necessary to 
combine with the mono-sulphide sulphur plus that necessary 
to combine with the thiosulphate sulphur plus that neces- 
sary to combine with the sulphate and sulphite sulphur. It 
must be noted how closely this figure agrees with the actual 
determination of lime. 
It will be noted also that in three of these mixtures, viz. 
the second, third and first, large quantities of the total lime 
used have not entered into solution and there appears 
therefore to have been a quite unnecessary expenditure 
of lime. 
The mixtures show a great similarity when the table is 
examined which sets forth the various forms of sulphur 
present when expressed in terms of the total sulphur, except. 
that there is a greater proportion of thiosulphate and 
sulphate sulphur in the first three than in the last, causing 
less polysulphidal sulphur in those than in number four. 
