THE SUBSTITUTION OF AN ALKALINE BASE IN 
CHLORIMETRY. 
BY 
JOHN SMYTH, Jun., ¢.E:, F.C.s. 
[Read May 21st, 1877.] 
In Chlorimetry, I consider that the use of a milky mixture of the 
sample of the bleaching powder to be tested, is a great incon- 
venience and source of loss. 
In the case where measured portions of the milky mixture are 
added to the chlorimetrical substance, there is a loss of the sample, 
from portions adhering to the hand or other stopper, during the 
frequent agitations, which are necessary, and there is a difficulty 
in maintaining an equality in strength, between the earlier and 
later added portions of the contents of the burette. 
The same objections prevail, where a measured portion is 
taken from a prepared stock mixture of the sample of bleaching 
powder, and acted upon by the chlorimetrical substance, as 
agitation is also necessary. In short in any case the reaction is 
not so palpable and satisfactory with a milky as with a clear 
liquid. 
I was therefore glad to find a simple method of always ob- 
taining a clear solution of the bleaching powder, containing all 
its chlorine, by merely dissolving it in an alkaline solution. 
I was led to adopt this method from the following circumstance. 
In the north of Ireland a solution of the bleaching salt of soda 
is used instead of one of lime for the finer fabrics of linen in the 
bleaching process, since the former liquid parts more slowly with 
its chlorine than the latter, a prolonged action is secured, and 
thereby the strength of the fabric is less affected. 
This alkaline bleaching liquid has long been manufactured in 
that district, formerly by the direct addition of chlorine to an 
alkaline solution ; but since the production of bleaching powder 
at a cheap rate by the reaction of carbonate of soda on a solution 
of the bleaching powder. 
In determining the amount of available chlorine in this liquid 
