e portion of electricity passing through it. Hence it was impossible to
distinguish the particular effects at the moments of making or breaking
contact from this constant effect. On using the thick wire helix (1055.),
the same results ensued.

1083. Proceeding upon the known fact that electric currents of great
quantity but low intensity, though able to ignite thick wires, cannot
produce that effect upon thin ones, I used a very fine platina wire at _x_,
reducing its diameter until a spark appeared at G or E, when contact was
broken there. A quarter of an inch of such wire might be introduced at _x_
without being ignited by the _continuance_ of contact at G or E; but when
contact was broken at either place, this wire became red-hot; proving, by
this method, the production of the induced current at that moment.

1084. _Chemical decomposition_ was next effected by the cross-wire current,
an electro-magnet being used at D, and a decomposing apparatus, with
solution of iodide of potassium in paper (1079.), employed at _x_. The
conducting power of the connecting system A B D was sufficient to carry all
the primary current, and consequently no chemical action took place at _x_
during the _continuance_ of contact at G and E; but when contact was
broken, there was instantly decomposition at _x_. The iodine appeared
against the wire N, and not against the wire P; thus demonstrating that the
current through the cross-wires, when contact was broken, was in the
_reverse direction_ to that marked by the arrow, or that which the
electromotor would have sent through it.

1085. In this experiment a bright spark occurs at the place of disjunction,
indicating that only a small part of the extra current passed the apparatus
at _x_, because of the small conducting power of the latter.

1086. I found it difficult to obtain the chemical effects with the simple
helices and wires, in consequence of the diminished inductive power of
these arrangements, and because of the passage of a strong constant current
at _x_ whenever a very active electromotor was used (1082).

1087. The most instructive set of results was obtained, however, when the
_galvanometer_ was introduced at _x_. Using an electro-magnet at D, and
continuing contact, a current was then indicated by the deflection,
proceeding from P to N, in the direction of the arrow; the cross-wire
serving to carry one part of the electricity excited by the electromotor,
and that part of the ar