The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1890-08-08
THE PRESS.
FRIDAY MORNING. AUG. s.
HOW A MOSAIC is MADE.
Visit to a London Glass Manu-
factory.
rPall Mall Gazette.l

velopments in glass manufacturing has
been in the art of working in glass mo-
sale, and they have reproduced in this
method Mr.. Holman Hunts picture of
"Christ among the Doctors, which many
people may remember in the old Water
color society's exhibition in 1887. The
mosaic, about eight feet wide and four
feet high, was made for the reredos of
Clifton college chapel. Few people have
the slightest idea of how a mosaic is
made.
1.-THE art of working in mosaic, the
most imperishable of wall decorations,
was known to the Romans" said Mr..
Powell, superintendent of a manufac-
tory, "and has been revived and practiced
at various times. Thus there was re-
vival in Raphael's time, and Titan also
made designs for mosaic. In our own
day it has been revived by Salviati, in
Venice, and it has been practiced in the
Vatican and at st. Peters in Rome under
the present and former pope for the pur-
pose of reproducing the works of the old
masters in an imperishable form. Most
of the work done in this country and ON
the continent for the last quarter of
century has been by Salviati.
"For instance, the designs of Alfred
Stevens for the spandrels in the dome of
st. Paurs are carried out by him, and
were executed in Venice. We have been
working at mosaic for about ten years,
and have introduced some very impor-
tant improvements. We have, more
over, trained all our own craftsmen, and
every part of the work. from the making
Of the glass to the completion of the
picture, is done by highly skilled En-
glish craftsmen"
HOW THE GLASS is MADE.
"And how are the cubes of glass made
and arranged into a picturer' "You
must begin at the beginning and see the
glass made" said Mr. Powell, leading
the way into the workshop. ''But first
let me show you what the old method
was. This" showing me a piece Of
Opaque colored glass, for all the world
like biscuit, sis piece of glass such as
is used in Venice. It is made by taking
big drop of molten glass and pressing
it out fiat-to about quarter of an inch
in thickness. These are made in every
color. They are cut into little cubes and
arranged to form the design, audit is the
cut face which forms the picture sur
face. The disadvantages are the disa-
greeable glitter Of the glass and the diff
ficulty of shaping the pieces"
''And the new methodr' / was shown
the maker of the glass atwork. The work.
man has shallow mold, into which he
sits from the perforated bottom of tin
jug a colored powder. From another
jug he Sits another thickness of white
powder, and then a considerable thick
ness of coarser powder, making alto
gether about a quarter of an inch. These
powders are of ground glass and are
fused by the heat of the fire into solid
tile, The first powder is of the color the
glass is intended to be, the second is
white, to give quality to the surface
color and to resist damp, and the third is
simply backing of coarser glass to give
strength and thickness.
The tile is then cut up into little pieces
with a steel American wheel into the
shapes required. 1.-THE advantage" con-
tinued Mr.. Powell, "besides the supe-
rior color is that we use the surface in
stead of the cut edge Of the tile for
the picture. And SO we can cut any
shape we require. Thus, as in Mr.. Hol-
man Hunts picture, we can cut pieces
into the shape of thumb nail, or of
nostril, or of parts of an eye, or of any
of the little bits of drawing which go to
make up picture. In the old way these
things would have to be made up of lit
tie cubes, and of course the shapes would
not have been nearly so accurate. By
our method we are enabled to approach
much nearer to pictorial effect-quite as
near as is desirable in this class of deco
ration"
HOW THE PIECES ARE PUT TOGETHER.
"And the putting Of the pieces to-
gether?" "There are several ways. The
most obvious is to cement the glass piece
by piece upon the stonework. But that
makes very uneven work, and it is diff
cult to make alterations. The methods
we actually practice are two-namely,
face down and face up. The former
is used for decorative panels and the lat
ter for important work, like pictures.
The method is this: We have tracing
made of, say, II head, which tracing is
pasted down ON plate of glass. The
little pieces of mosaic are then, after
much careful selection and cutting, put
down upon their places on the tracing
and fixed with weak cement, and so bit
by bit the whole is made up.
1.-THE advantage is that we see what
we are doing as we go on, and that al
terations are easily made When the
work is finished in this way it is ready
for transferring permanently to the
stone wall or to a slab of slate This
is easily done. We take piece of linen,
such as architects use for tracing and
cement it all over the face of the pieces
OF glass. When this is hard the linen
with all the pieces of mosaic is stripped
off the glass plate. The slab of slate or
the wall is then prepared with cement
upon which the mosaic, held together
by the linen, is pressed and left 10
harden. The linen is then washed off
and the finished mosaic exposed to view
Al +b;e ic how a o1aco ,,o--... ".