296 On the Procefs of Bleaching with 
was then weighed again, and the difference between its pre- 
fent and original weight was noted. The fame method was 
obferved in all the experiments. 
Experiment I. To half an ounce of oxygenated muriatic 
acid, I added a folutioa of indigo in acetous acid*, drop by 
drop, till the oxygenated acid ceafed to deftroy any more co-’ 
Jour. It deftroyed the colour of 160 grains of the acetite of 
indigo. 
Experiment II. A repetition of Experiment 1. The colour 
of 165 grains of acctite of indigo was deftroyed in this 
experiment. 
Experiment IT]. A repetition of Experiments 3. & 17. 
The colour of 160 grains of the acetite was deftroyed. 
Experiment 1V. To half an ounce of the oxygenated mu- 
riatic acid, were added 8 drops of pure potafh in a liquid 
fate. This quantity of alkali was about fufficient to deprive 
the acid of its noxious odour. This mixture deftroyed the 
colour of 150 grains of the acetite of indigo. — . 
Experiment V. A repetition of Experiment tv. The co- 
lour of 145 grains of the acetite was deftroyed. 
Experiment VI. To half am ounce of the oxygenated mu- 
riatic acid, to drops of the fame alkali were added. It de- 
ftroyed the colour of 125 grains of the acetite of indigo. 
Experiment VII. A mixture of half an ounce of the oxy- 
genated acid, and 15 dyops of the alkali, deftroyed the co- 
lour of 120 grains of the acctite of indigo. 
Though I had taken the precaution of avoiding the ful- 
phuric acid, for the reafon {tated in the foregoing note, I 
was not quite fatisfied with thefe experiments, on account 
* It has been ufual to eitimare the ftrength of the oxygenated muriatic 
acid by a folution’ of indigo in fulphuric acid. This method was inads 
miffible in thefe experiments on the comparative ftrength of the bleaching 
Jiquor, with and without alkali; becaufe the fulphuric acid would have 
cecompofed the muriat of potafh, and thereby produced errors. I there- 
fore added to a fohation of indigo in fulphuric acid, after it had been di- 
Juted with water, acetite of lead, till the fulphuric acid was precipitated 
with the lead. The indigo remained diffolved in the acetous acid. 
