420 
Proceedings of the Royal Society 
ascertained by means of a very carefully prepared normal sulphuric 
acid, containing 49 grms. II 2 S0 4 in a litre. 10CC. of this acid 
saturated 42'7 CC. caustic soda, and 4T8 CO. baryta water, whence 
one litre caustic soda contains 9-3677 grms. NaHO, and one litre 
baryta water 20450 grms. BaH 2 0 2 . 10 CC.of the above-mentioned 
chloracetic acid saturated 14 7 CC. caustic soda and 144 CC. baryta 
water. 
In every experiment 10 CC. chloracetic acid solution were sealed 
up in a tube, and introduced directly into the boiling water bath. 
After the reaction was finished, it was transferred immediately to 
a vessel of cold water. By this means the time of heating up to 
100° and of cooling down again to the surrounding temperature 
was reduced to a minimum. 
The chloracetic acid solution was prepared in the middle of last 
November, and although it has now stood at the ordinary tempe- 
rature of the laboratory for over four months, its saturating power 
has not changed to a sensible extent. It is true, however, that it 
gives a slight opalescence with solution of nitrate of silver. It 
appears then that the decomposition of monochloracetic acid by a 
large excess of water at the ordinary temperature is infinitely slow. 
In the experiments at 100° C. the same quantity, namely, 10 CC. 
of the acid solution, was invariably employed, In the following 
table showing the results, the first column contains the duration 
of the experiment in hours ; the second the number of CC. caustic 
soda or baryta water required to saturate the resulting acid, and 
the third gives the percentage chloracetic acid decomposed as 
calculated from column 2. No fraction smaller than 0'5 is given, 
this being the limit of possible errors of observation : — 
ever, altering the strength of the solution. My principal objection to it was 
its great tendency to crystallise even in solutions a long way removed from 
saturation. 
Table 
