crystallized silicon held at the open end will be found to immediately
take fire in the escaping fluorine. The best mode of obtaining the
fluoride of platinum for this purpose is to heat a bundle of platinum
wires to low redness in the fluorspar reaction tube in a rapid stream
of fluorine. As soon as sufficient fluoride is formed on the wires,
they are transferred to a well stoppered dry glass tube, until
required for the preparation of fluorine.


ACTION OF FLUORINE UPON NON-METALLIC COMPOUNDS.

_Sulphureted Hydrogen._--When the horizontal tube shown in Fig. 3 is
filled with sulphureted hydrogen gas and fluorine is allowed to enter,
a blue flame is observed on looking through the fluorspar windows
playing around the spot where the fluorine is being admitted. The
decomposition continues until the whole of the hydrogen sulphide is
converted into gaseous fluorides of hydrogen and sulphur.

_Sulphur dioxide_ is likewise decomposed in the cold, with production
of a yellow flame and formation of fluoride of sulphur.

_Hydrochloric acid_ gas is also decomposed at ordinary temperatures
with flame, and, if there is not a large excess of hydrochloric acid
present, with detonation. Hydrofluoric acid and free chlorine are the
products.

Gaseous _hydrobromic_ and _hydriodic acids_ react with fluorine in a
similar manner, with production of flame and formation of hydrofluoric
acid. Inasmuch, however, as bromine and iodine combine with fluorine,
as previously described, these halogens do not escape, but burn up to