attacked in the cold, and emitting a brilliant blue light which is
surrounded by a halo of the fumes of boron fluoride.

_Sulphates_, _nitrates_ and _phosphates_ generally require the
application of more or less heat, when they too are rapidly and
energetically decomposed. Calcium phosphate is attacked in the cold
like lime, giving out a brilliant white light, and producing calcium
fluoride and gaseous oxyfluoride of phosphorus, POF_{3}. _Calcium
carbonate_ also becomes raised to brilliant incandescence when exposed
to fluorine gas, as does also normal _sodium carbonate_; but curiously
enough the bicarbonates of the alkalies do not react with fluorine
even at red heat. Perhaps this may be explained by the fact that
fluorine has no action at available temperatures upon carbon dioxide.


ACTION OF FLUORINE UPON A FEW ORGANIC COMPOUNDS.

_Chloroform._--When chloroform is saturated with fluorine, and
subsequently boiled, carbon tetrafluoride, hydrofluoric acid and
chlorine are evolved. If a drop of chloroform is agitated in a glass
tube with excess of fluorine, a violent explosion suddenly occurs,
accompanied by a flash of flame, and the tube is shattered to pieces.
The reaction is very lively when fluorine is evolved in the midst of a
quantity of chloroform, a persistent flame burns beneath the surface
of the liquid, carbon is deposited, and fluorides of hydrogen and
carbon are evolved together with chlorine.

_Methyl chloride_ is decomposed by fluorine, even at -23°, with
production of a yellow flame, deposition of carbon, and liberation of
fluorides of hydrogen and carbon and free chlorine. With the vapor of