The Quarterly Journal of Science, Literature and the Arts, July-December, 1827Various
Science
The Quarterly Journal of Science, Literature and the Arts, July-December, 1827
Various
Arts -- Periodicals; Science -- Periodicals; Technology -- Periodicals
12. Now although it may be supposed that in the former portion that
part of the chlorine, which, in acting energetically, had produced
chloric acid, could not be detected by the nitrate of silver, yet
more than a sixth of the small portion which remains cannot be thus
hidden; and even that quantity is diminished by the sulphuric acid
present in excess, which tends to make the chlorine in the chlorate
sensible to nitrate of silver: so that the experiment shews that
nearly 59 parts out of 60 of the chlorine in M. Labarraque’s liquid
are in a state of weak combination with the carbonated alkali, and
may be separated by acids in its original condition; that this
quantity is probably wholly available in the liquid when used as a
bleaching or disinfecting agent; that little, if any, of the chlorine
forms chloride of sodium and chlorate of soda with the alkali of
the solution; and that the portion of chlorine used in preparing
the substance which is brought into an inactive state, is almost
insensible in quantity.
13. The peculiar nature of this compound or solution, with the
results Mr. Phillips had shewn me (8), obtained by evaporation of a
similar preparation to dryness, induced me to try the effects of slow
evaporation, crystallization, heat, and air upon it. In the first
place five equal portions of the solution prepared by myself were
measured out: two were put into stoppered bottles, two were put into
basins and covered over with bibulous paper, and one was put into a
basin which was left open; all were set aside in an obscure place,
and remained from July 16th to August 28th. Being then examined, the
portions in the basins were found crystallized and dry; the crystals
were large and flat, striated and imperfect, resembling those formed
[p089] in a similar way from carbonate of soda. They were not
small and acicular, were nearly alike in the three basins, and had
effloresced only on a few minute points. A part of one portion, when
dissolved, gave a solution, having an alkaline taste, without any
of the pungency of Labarraque’s liquid; and which, when tested by
turmeric paper, reddened, but did not bleach it.
14. One of these portions that had effloresced least was selected,
and being dissolved, was compared in bleaching power upon diluted
sulphate of indigo, with one of the portions of solution that had
been preserved in bottles. The former had scarcely any visible
effect, though sulphuric acid was added to assist the action; a
single measure of the indigo liquor coloured the solution permanently
blue, whereas seventy-seven such measures were bleached by the
portion from the bottle. Hence the process of slow crystallization
had either almost entirely expelled the chlorine, or else had caused
it to react upon the alkali, and by entering into strong chemical
combination as chloride and chlorate, had rendered it inert as a
bleaching or disinfecting agent.
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