inside must have a more contracted surface
than the outside. Well; we shall see. It
has to be annealed, before anything more can
be done to it, and for this purpose, it is
carried to the kiln, where it is to be well
baked, and gradually withdrawn into a lesser
and lesser heat, until it will bear what else it
has to undergo. As we cannot stand here
for a day or two till it is done, we must
transfer our attentions to another cylinder, to
see how the splitting is effected.

The diamonds, for cutting, are shown to us.
One is mounted as on one point of a pair of
pincers, the diamond looking inwards. The
pincers are mounted upon wheels. This is for
cutting off the edge of the cylinder, which is
more or less jagged. The little carriage runs
round under the upright cylinder, the diamond
marking the glass as it travels; and a gentle
tap severs the jagged end at the mark. Next,
the cylinder is laid along upon a table, and
another mounted diamond is run through the
inside of it, from end to end, guided by a
ruler. Another tap, and there is a split
along the line, and the edges actually overlap.
The glass is seen to be thicker than it is to
remain. It will lose one fifth, or one sixth of
its thickness in the grinding. A curious fact
is observed here. Looking at the edge of a
piece of red glass, we see that it is not red
throughout—that, in fact, the glass, seen sideways,
is greenish; but how this happens we
cannot divine. It is done by taking up first a
little of the red honey from the ruby glass-pot,
and afterwards white—again and again,
in proportion to the intended paleness of the
hue. Thus, the red, while completely incorporated
in substance with the rest, is spread
over only the inner surface; and thus, when
cut, the sheet can be embossed with white
figures. Red or white, the cylinder is now to
become a sheet of glass.

We adjourn to the mouth of a kiln, where
we see that a slab of stone, moveable, forms
the floor. On this slab lies a sheet of glass;
and our cylinder is to be unrolled upon it, or
its lower side would be made rough by
contact with the stone. A little lime or chalk
is sprinkled on the sheet, and then the cylinder
is laid down upon it. As it heats, it begins
to gape at the slit. The process is aided by
the man at the kiln. He takes up a pole
which has a wooden block at the end of it,
thrusts in the block, and proceeds to iron out
the relaxing cylinder. His block begins to
smoke, and presently throws out sparks, more
and more; but he perseveres until every corner
is levelled; the sheet lies as flat as a pancake,
and its two surfaces are equalised, in its semi-fluid
condition. By observing the reflection
of the fire on its surface, we see that it is
rapidly melting. But it is not to melt away;
so the slab is drawn away backwards, by a
stout chain; and another is to take its place
from one side.

We go round to see what becomes of the
sheet. We find it in a somewhat cooler part
of the kiln, about to be removed, that the
stone slab may go back to its proper work.
A boy is to effect the removal. He lifts up
the sheet with a long ''fork," as he calls it,
and gently lays it on the top of a pile of
predecessors, which are gradually cooling.
When nearly cooled, they are to be transferred,
in the iron box which now contains
them, and where they are to stand on edge,
separated by iron bars, to a sort of railway
truck, where they stand, shut up in their box,
until they have become accustomed to a natural
temperature, and may be carried on. to the
grinding. There we must leave them, while
we take a look at the treatment of two other
kinds of glass—flint-glass, or crystal, and
crown glass.

There is no flint now really used in the
manufacture, though there was when crystal
glass was called after it. Flints were, in
those days, heated red-hot, and thrown into
cold water, when they fell to pieces, so far as
to be easily reducible to powder. It is still
easier, however, to pick up the sand ready
powdered at Lynn and in the Isle of Wight.
Red lead is added, to give density to the
glass; but in what proportions we did not
inquire here, having learned elsewhere that
that is the one question which a stranger
ought not to ask. It is the grand secret of
most glasshouses. Red lead also promotes
the melting of the sand; it gives a greater
refracting power, and a higher lustre; and it
is some protection against fracture from
sudden changes of temperature. It renders
the glass more ductile in the working also;
but there must not be too much of it, or the
material will be too soft. In these works,
the flint glass has a furnace to itself—built
for it. It is melted in crucibles, or small
pots, over and over again, until it is pure. It is
left in the pots, and the furnace is shut up,
and allowed to cool very slowly; when the
pots fall away, and leave the glass in masses.
A man holds each mass between his eye and
the light; and, if he sees any speck, he splits
the glass, and removes the offending particle.
Peeping into the annealing oven, we see flat
cakes of flint glass, about an inch thick; and
it is with a sort of veneration that we look
upon them. They have grand work to do
soon. They are to bring down to us much
that is too high, and up to us much that is
too small, for our discovery without their
help. They are to open to us the spectacle
of starry systems—reach beyond reach, until
our faculties can endure no more. They are
to show us (what we could not believe without
seeing) how every drop of water in a
stagnant pond is thickly peopled with living
animals, and how whole quarries and sea-beaches
are composed of the remains of dead
animals. They are to separate the rays of
the sun into parts for us; and to enable the
aged to read and work, forgetting their
years; and to repair many a mischief of imperfect
sight; and to improve the beacon-