3 6 Faraday's Researches

experimented with, in a similar manner, exactly the same
results occurred.

134. Whenever the current passed in these cases, there was
decomposition of the substances; but the electro-chemical part
of this subject I purpose connecting with more general views
in a future paper.1

135. Other substances, which could not be melted on glass,
were fused by the lamp and blowpipe on platina connected
with one pole of the battery, and then a wire, connected with
the other, dipped into them. In this way chloride of sodium,
sulphate of soda, protoxide of lead, mixed carbonates of potash
and soda, etc., etc., exhibited exactly the same phenomena as
those already described: whilst liquid, they conducted and
were decomposed; whilst solid, though very hot, they insulated
the battery current even when four troughs were used.

136. Occasionally the substances were contained in small
bent tubes of green glass, and when fused, the platina poles

introduced, one on each side.
In such cases the same gen-
eral results as those already
described were procured; but
a further advantage was ob-
tained, namely, that whilst
the substance was conduct-
Fig- 7- ing and suffering decom-
position, the final arrangement of the elements could be
observed. Thus, iodides of potassium and lead gave iodine at
the positive pole, and potassium or lead at the negative pole.
Chlorides of lead and silver gave chlorine at the positive, and
metals at the negative pole. Nitre and chlorate of potassa
gave oxygen, etc., at the positive, and alkali, or even potassium,
at the negative pole.

137. A fourth arrangement was used for substances requiring
very high temperatures for their fusion. A platina wire was
connected with one pole of the battery; its extremity bent into
a small ring, in the manner described by Berzelius, for blow-
pipe experiments; a little of the salt, glass, or other substance,

1 In 1801, Sir H. Davy knew that " dry nitre, caustic potash, and soda
are conductors of galvanism when rendered fluid by a high degree of heat "
(Journals of the Royal Institution, 1802, p. 53), but was not aware of the
general law which I have been engaged in developing. It is remarkable,
that eleven years after that, he should say, " There are no fluids known
except such as contain water, which are capable of being made the medium
of connection between the metal or metals of the voltaic apparatus."—
Elements of Chemical Philosophy, p. 169.1*

quid matter, that con-