354 Prof. Draper on the Allotropism of Chlorine 
the exception of a small bubble, amounting in volume to ;,.- of 
the water. This bubble, which was left after the chlorine was 
re-condensed, I found in three different experiments contained 32, 
33, and 36 per cent. of oxygen,—the remainder being nitrogen ; 
but this being nearly the constitution of the gas which is dis- 
solved in ordinary water, the source from which the small bubble 
came was inferred to be the water used in these experiments. 
2d. One of the bulbs was painted black all over with India ink. 
Its temperature now rose much higher than in former experi- 
ments when it was set in the sun, but not a bubble of oxygen 
appeared. 
X. When chlorine water has been exposed to the sun, the 
oxygen accumulated in it is readily expelled by raising the tem- 
perature. 
Having exposed one of the bulbs used in the last experiment, 
until it was actively evolving gas, I raised its temperature with 
the spirit lamp until the bulb was full of gas. But, on cooling, 
this gas did not all condense as in the last instance, a large quan- 
tity remained behind. 'This was oxygen. 
These ninth and tenth facts are of further interest, as bearing 
upon a question which has been much discussed by chemists,— 
the nature of the bleaching compounds of chlorine. The chloride 
of lime, and other such substances, probably have the same the- 
oretical constitution as chlorine water. Berzelius and Balard sup- 
pose, that in this solution chlorous or hypochlorous acids exist. 
It might be inquired, if this be the condition of things, why does 
not an exposure to heat alone evolve oxygen, for chlorous acid is 
exceedingly liable to decomposition by slight elevation of tem- 
perature, and we should be justified in inferring that if any of 
this acid is to be found in chlorine water, it would be decomposed 
at the boiling point. M. Millon adopts the view that the bleach- 
ing compounds are metallic chlorides analogous to the corres- 
ponding peroxides. But the ninth fact seems incompatible with 
this view. If chlorine water be analogous to peroxides of hydro- 
gen, and this last be what its name imports, and not merely 
oxygenated water, it is difficult to understand why when chlorine 
water is thus boiled oxygen is not given off. If the atom of 
chlorine and the atom of oxygen in this body are placed under 
the same relations to the atom of hydrogen, it seems necessary 
that the chlorine atom at 212° Fahr. should expel the oxygen 
