Los Angeles herald., 1906-08-12

At Murano glass mirrors were first made af-
ter the manner suggested by Aristotle-by Ilac-
ing metallic sheet lack of the glass. The
experiment. did not prove satisfactory, and
rnetal mirrors remained in vogue till the be-
g,rnm of the sixteenth century, when two
glass5makers of Murano discovered the method
OF making mirrors which had for several years
prevailed in Germany.
The German process was as follows: Melt
ed lead or tin was blown with a pipe into
hollow ball of glass, while hot, thereby en-
tirely coating its interior. When the glass
had cooled, it was cut into small, round mir
rors.
The two Muranese improved on this method
by substituting an amalgam of tin and quick
silver in place Of the metals used by the Ger.
mans: Then they petitioned the Council of
the Ten that the right to manufacture these
mirrors be granted them exclusively for TWEEN
ty-five years. The desired privilege was
granted them for twenty years.
Wonderful success attended the enterprise,
and, when the twenty years had expired hun
dreds engaged in it. Indeed, SO numerous
were the mirrormakers, the Venetian govern
ment separated them from the other glass
for their benefit
Gradually the manufacture of glass mirrors
advanced toward perfection, and no one did
more in this direction than Liberale Motta,
who hourished at Murano about $780, and
made them OF size previously unattainable."
Unwilling longer to pay the enormous trib
ute necessary to obtain the Venetian looking
glasses, Colbert, Minister of France under
Louis XIV, resolved to found mandatory
at Paris, and in 1865 contrived to secure eigh-
teen mirror-makers from Murano.
A mandatory was Immediately established
in the Faubourg st. Antoine. The workmen,
however, grew discontented, and, on the
ground that the promises by which they had
been induced to leave Murano had not been
fulfilled, abruptly took their departure from
Paris.
Colbert, completely discouraged, was about
to close his factory when he learned that at
Tourlaville, some forty miles from Paris, look
ing-glasses of the Venetian style were made
under the direction of Richard Lucas de Ne
hou.,
He arranged to have the works at Tourla-
vile annexed to the Partisan manufactory,
and thenceforward, in the French capital, the
industry prospered finely.
In 1858 a son of Lucas de Nehou discov-
cred that glass, like metal, could be cast into
plates larger than could be obtained by blow
ing and rolling-the only method previously
known for obtaining glass plates the dis
covery marked an era in the manufacture of
mirrors.
There have been and are various processes
for coating mirrors with quicksilver, but they
are so similar to one another that an idea of
the general principle is easily gained from
description Of either.
On a plane surface of tin, that has been
carefully cleaned, quicksilver is poured. Hav-
ing been smoothed with the hand Or brush,
the 'silveredS surface is covered with paper.
The "glass" is then placed ON the paper, and
the paper is withdrawn. Heavy weights press
the excess of quicksilver from beneath the
glass, and are allowed TO remain till the "foil'
has become thoroughly fixed to the glass.
A process invented by M Petitpeau, in
1855, of silvering with ammonia, tartare acid
and nitrate of silver, does away with the IN
jurious effects resulting to the workmen where
- R.af otad h.. I.
method becomes spotted. 1t is believed.