primary wire by the sudden rushing into
it of a stream of electricity.

The first endeavours to work the new
coil were frustrated by its own powers of
destruction. It melted the platinum, and
burnt up the brass of the original contact
breaker. When used with a small amount
of condenser surface, it burst the primary
wire into fragments, and escaped from it
laterally. When these difficulties were
overcome, and the whole apparatus was in
order, it afforded a spark, or rather a
flash of lightning, twenty-nine inches in
length, and apparently about a third of an
inch in width. The length was measured,
of course, by the distance between the
terminals, and when this exceeded twenty-
nine inches, no distinct flash was given.
For a distance within its power to cross,
it would almost seem that the electricity,
like a strong leaper, makes an effort
proportionate to the resistance to be
overcome. When the terminals are distant,
but still within the twenty-nine inch
limit, the flash strikes upon the disc
with a heavy shock and a loud report.
When they are near together, or within
two or three inches, the flash gushes forth
without noise, and lazily, like a spurt of
molten metal, or of dense flame; and from
this "flaming spark," as it is called, the
flaming portion can be blown aside by
bellows, leaving the actual course of the elec-
tricity distinctly visible. Either the flaming
spark or the longer one will perforate
considerable thicknesses of glass, and five
inches of solid plate glass have already
been pierced by it. At one visit we chanced
to see a remarkable illustration of the way
in which metallic surfaces may serve to
attract lightning. The outer covering of
the coil displays the name and address of
Mr. Apps, its maker, in gold letters of
considerable size. In taking a long spark, the
stands that support the terminals were
placed nearer to the coil than usual; and
the attraction of these gold-leaf surfaces
was sufficient to divert the spark from its
course, and visibly to break it up into por
tions. In the darkened theatre at the
Polytechnic, the long flash lights up the room and
the audience with the peculiar lurid glare so
well known as an effect of brilliant lightning
at night, and displays the features
and action of every one present. But it is
curious to note that, the flash being of
instantaneous duration only, it allows no
motion to be seen. We should think, if
guided by our consciousness alone, that the
flash lasted an appreciable time; but this
would be an error, due to the persistence
of the impression on the eye, after the
flash itself had ceased. If the room be
made perfectly dark, and if the spectators
all raise their arms and wave their hands
to and fro as quickly as they can, the flash
will display the position of the arms, but
not the movements of the hands. While
the flash lasts, the hand has no time to move,
and is consequently seen, as if motionless,
in the position in which the flash finds it.
It is in contemplation to exhibit the same
effect in a more complete way by affixing a
picture to a revolving disc. When the
disc revolves so rapidly that no outlines of
the picture can be distinguished by means
of any ordinary light, they will be perfectly
seen in a darkened room by the light
of the flash. It lasts so short a time, that
the revolving disc does not change its
position in the brief period.

It is the smallest part of the advantage
expected from the new coil, that it allows
all the luminous and all the destructive
phenomena of chamber electricity to be
exhibited, in hitherto unapproached beauty
and intensity. Men of science anticipate
from it new discoveries of high importance.
In the intervals between the public exhibitions
of artificial lightning, the effects of
the coil are being closely studied by those
who are best able to appreciate them; and
we believe no long time will be required in
order to prove that Mr. Pepper, in his
ever zealous catering for the entertainment
and instruction of his especial public, has
laid the foundation of real and solid scientific
progress.