276 BALARD’S RESEARCHES CONCERNING THE NATURE OF 
The salts of lead possess no advantage over those of mereury. If a 
solution of acetate or nitrate of lead be poured into a decolorizing 
chloride, a precipitate of chloride of lead is immediately formed ; but 
this chloride is itself susceptible of being altered by the chlorite. If it 
is not soon separated from the liquor, it becomes quickly brown, is 
converted into peroxide, and gives out a strong smell of chlorine. This 
double phenomenon is undoubtedly effected by the decomposition of 
the chlorous acid. 
Since the salts of lead did not, any more than those of mercury, lead 
to the end intended, I was compelled to have recourse to the action of 
those of silver ; they are more costly, it is true, but they apparently 
would be followed with more success. My attempt was not altogether 
unsuccessful. Nevertheless the employment of the salts of silver is 
attended with some inconveniences which it is requisite to state. 
If a neutral solution of nitrate of silver be precipitated by a solution of 
chloride of lime, containing a slight excess of lime, a great quantity of 
chloride of silver is precipitated, and there is formed at the same time 
oxide of silver, which imparts a grey colour to the deposit obtained. 
The supernatant liquid is strongly decolorizing; but if an attempt be 
made to separate it by filtration, a brisk effervescence is produced as 
soonas alittle has filtered, and when the filtration is over the liquor has 
completely lost its decolorizing property. The gas which is evolved in 
this case is oxygen. Berzelius had previously observed the pheenome- 
non which I have now mentioned, and discovered the cause of it. I 
have ascertained in operating directly with the chlorites and the oxide 
of silver, that these salts occasioned the formation of chloride of silver 
and a disengagement of oxygen. This oxygen is produced, both from 
the chlorous acid and the decomposed oxide. A portion of this oxygen 
gas evolved is absorbed by the portion of oxide in excess in the liquor, 
and converts it into peroxide, whilst the remainder is given out in the 
state of gas. In trying to obtain free chlorites, the precipitation of oxide 
of silver must be avoided, and the decolorizing chlorides must have no 
excess of alkali, which is avoided by neutralizing them with nitric 
acid; but it is requisite not to add excess of it, which would be as 
active, though a different cause of the decomposition of the chlorite. 
If, indeed, a solution of chloride of lime supersaturated with nitric 
acid be precipitated by nitrate of silver, the mass of chloride of 
silver formed is soon raised by abundant bubbles of chlorine gas, and 
the decolorizing property is in a great degree lost. If an attempt be 
made quickly to remove the chloride of silver, which is the cause of 
this decomposition, from the supernatant liquid, by throwing it in a 
cloth and pressing it strongly, the reaction is accompanied with a 
disengagement of a very considerable degree of heat. Some direct expe- 
riments, which I shall state hereafter, have proved that the chlorous 
