Bodies Subject to the New Law	37
was melted on this ring by the ordinary blowpipe, or even in
some cases by the oxy-hydrogen blowpipe, and when the drop,
retained in its place by the ring, was thoroughly hot and fluid,
a platina wire from the opposite pole of the battery was made
to touch it, and the effects observed.
138.	The following are various substances, taken from very
different classes chemically considered, which are subject to»
this law.   The list might, no doubt, be enormously extended;
but I have not had time to do more than confirm the law by a
sufficient number of instances.
First, Water.
Amongst oxides ;—potassa, protoxide of lead, glass of anti-
mony, protoxide of antimony, oxide of bismuth.
Chlorides of potassium, sodium, barium, strontium, calcium,
magnesium, manganese, zinc, copper (proto-), lead, tin (proto-),
antimony, silver.
Iodides of potassium, zinc and lead, protiodide of tin, perio-
dide of mercury; fluoride of potassium; cyanide of potassium;
sulpho-cyanide of potassium.
Salts. Chlorate of potassa; nitrates of potassa, soda, baryta,
strontia, lead, copper, and silver; sulphates of soda and lead,
proto-sulphate of mercury; phosphates of potassa, soda, lead,
copper, phosphoric glass or acid phosphate of lime; carbonates
of potassa and soda, mingled and separate; borax, borate
of lead, per-borate of tin; chromate of potassa, bi-chromate
of potassa, chromate of lead; acetate of potassa.
Sulphurets. Sulphuret of antimony, sulphuret of potassium
made by reducing sulphate of potassa by hydrogen; ordinary
sulphuret of potassa.
Silicated potassa; chameleon mineral.
 139.	It is highly interesting in the instances of those sub-
stances which soften before they liquefy, to observe at what
period the conducting power is acquired, and to what degree
it is exalted by perfect fluidity.   Thus, with the borate of lead,
when heated by the lamp upon glass, it becomes as soft as
treacle, but it did not conduct, and it was only when urged by
the blowpipe and brought to a fair red heat, that it conducted.
When   rendered   quite   liquid,   it  conducted   with   extreme
facility.
 140.	I do not mean to deny that part of the increased con-
ducting power in these cases of softening was probably due to
the elevation of temperature (168, 181);  but I have no doubt
that by far the greater part was due to -the influence of the