Arricue XII. 
Researches concerning the Nature of the Bleaching Compounds 
of Chlorine; by J. A. BALARD. 
From the Annales de Chimie et de Physique, vol. lvii. p. 225. 
Amone the remarkable properties which chlorine possesses, there 
is. one which became advantageous to manufactures very shortly after 
its discovery, viz. its energetic action on colouring matter. - The illus- 
trious Swede to whom we owe the knowledge of this body, mentioned 
the facility with which it destroys vegetable colours ; but that which to 
Scheele was merely an interesting experiment, became to Berthollet 
the basis of a new art. Berthollet conceived the happy idea of apply- 
ing the decolorizing property of chlorine to the purpose of bleaching, 
and the suecess which he obtained even in his first attempts exceeded 
his hopes. Up to this period, cotton and linen manufactures were 
spread in meadows, and by exposing them alternately moist and dry to 
heat and cold, light and shade, they were indeed, after a very long 
time, perfectly bleached. 
The eagerness with which a new process was welcomed will be con- 
ceived, when manufacturers could produce by it in a few hours what 
previously occupied several months. The new process of bleaching, to 
which public gratitude gave the name of the Berthollean method, was 
generally adopted, and chlorine thus proceeded from the laboratory 
of the chemist to the workshop of the arts. Manufactures were first 
bleached with chlorine gas, and afterwards with the aqueous solution ; 
but it was soon found that its penetrating smell, and its powerful action 
on the lungs, were very prejudicial to the workmen employed. In his 
endeavours to free them from these dangerous exhalations, Berthollet 
perceived that by the addition of a little quicklime, and even carbon- 
ate of lime or of magnesia, the penetrating smell of the chlorine was 
removed from the aqueous solution, without diminishing its bleaching 
power. This important observation conducted him to another still 
more important. He stated that if, instead of dissolving the alkali in 
aqueous solution of chlorine, a current of the gas was made to pass: 
into the alkaline solution, it would dissolve a much larger quantity than 
mere water, and the liquid possessed decolorizing power in a much 
higher degree. 
These new compounds, in which the chlorine seemed in some degree 
