Nov. i, 1885.] The Australasian Scientific Magazine. 
133 
The Substitution of an Alkaline Base in 
Chlorimetry. 
By John Smyth, Junr., C.E., &c. 
In Chlorimetry, I consider that the use of a milky mixture of the sample 
of a bleaching powder to be tested, is a great inconvenience and a source 
of loss. 
In the case when 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, when 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 obtaining a 
clear solution of the bleaching powder, containing all its chlorine by merely 
dissolving it it an alkaline solution. 
I was led to adopt this method from the following circumstances. 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. 
The alkaline bleaching liquid has long been manufactured m that 
district, formerly by the direct addition of chlorine in an alkaline solution; 
but siu’ce the production of bleaching powder at a cheap rate by the reaction 
of carbonate of soda in a solution of the bleaching powder. _ 
In determining the amount of available chlorine in this liquid from 
time to time by the usual methods, so much more satisfactory results were 
obtained than in testing bleaching powder, that I made a number of 
investigations to determine whether correct and expeditious results could 
be secured by converting the latter into the former. The result was that, 
at least as accurate determinations of the amount of available chlorine in 
the several samples were obtained by this means as by using the milky 
solution. 
As an excess of alkali is no inconvenience in testing, and thereby the 
liquid settles more readily and is more easily filtered, the usual mode of 
