Omaha daily bee., 1895-09-29

I iNiT'hS WIN NNntIlNtu tnrm. 1nte remark.
however by no means applies TO the glass
,emon-squeezer, which is already a familiar
household utensil The inventor OF II is said
TO nave sold his rights for $50, 900.
me most meritorious inventions do not
always obtain adoption. For example sew
eral good processes for making glass bot
| Ies by machine have been patented Dut
| they arc not used to any great extent he
cause the trade OF the bottle makers is con-
serEatVe. aud the workmen's unions are
against tue introduction Of machinery. IL
! Is the old story, which has been repeated In
| almost every branch of Industry Glass
| pitchers, handle and all In one piece are
Low Low oelns produced in molds by pressure
me upper part having been formed In the
mold the lower part Of the pitcher is dis
| tended to the requisite globular shane by
! forcing compressed air downward through
| tho neck.
PRESSED GLASS.
| The art Of making pressed glass is an
| American invention Many centuries ago
buttons and such little things of glass were
produced by means OF primitive pinch-molds
| But now this branch Of manufacture has
been brought to such perfection that cups,
| DoWls ana other articles of pressed glass
closely initiate the costly cut glass. The
| process is very simple. A measured duan-
! tity OF melted glass being placed in the bot
| tom OF the mold. down comes a punger.
winch forces the vitreous fluid into all parts
OF the mold. When cold the east" thus
! obtained is taken out of the mold The
| latter, OF course, may be Of any shape de-
| sired, and of as elaborate pattern One
OF the most remarkable inventions in glass,
| by the way. was that of a Venetian named
| Joquin, in 1866. He noticed that the scales
| OF fish called the bleak gave a milky hue
TO water, and that glass beads dipped into
such water looked like pearls when dried
subsequently the idea was conceived OF
making hollow beads Of glass and lining
them with the peculiar substance from the
scales OF the fish, and It is this way that the
so-called Roman pearls are now manufac-
tured 1t Is to this substance that the
iridescenCe of the scales of many species OF
fishes is due.
To the Venetians, also, must be attributed
the earliest manufacture of mirrors on a
commercial scale, soon after the beginning
OF the sixteenth century. Before that time
small convex mirrors of glass were pro-
duced in Germany by blowing glass globes
into which melted mixture of tin, anti
lnony and resin was passed through tube.
The globe thus coated inside was subse-
quently cut into lens shaped pieces. Venice
enjoyed a monopoly of mirror making for
100 years. The workmen had remarkable
privileges, but any one of them who went
away was obliged to return on requistion,
the penalty for disobedence being the i'm
prsonment Of his nearest relatives IL then
he refused to come back emlssaries were
sent to Kill him. Nevertheless Colbert when
prime minister OF France in 1865 imported
twenty Venetian mirror-makers. The dis
covery of plate-gass gave great impetus
to the industry. and since that day the French
mirrors have been the best.
EARLY VENETIAN MIRRORS
IN the manufacture Of the early Venetian
mirrors sheet of tnfoil was laid upon a
nat surface, and mercury was poured over
II. Then sheet of glass was slid carefully
over the mercury, and heavy weights were
placed upon 1t for the purpose of squeezing
out all but a thin film of the quicksilver
Inc tin and mercury having combined, the
mrIor, with few finishing touches. was
ready for use. This process continued to be
employed up to about sixty years ago, when
~ was superseded by Baron Liebgs inven-
ton. Mercury is no longer employed, its
use use peing attended by danger to health In
old times the teeth of the workmen used to
faIl out, and they suffered from variety
OF distressing disorders. Now solution OF
pure silver Is used instead, the metal being
deposited on the. glass by chemical means
But the greatest achievement of glass
making up to date is the production OF lenses
for big telescope, such as that of the Lick
observatory in California. The most i'm
portant difficulty is to get piece Of clear
glass that is large enough for the purpose.
The ingredients are melted In an earthen
pot, and the mixture is then permitted to
cool slowly After being melted and cooled
the shape of a disk. All over the surface
OF the disk are found impurities which must
be removed by cutting off portions of the
substance: Many more MEETINGS and re-
is as free as possible from bubbles and other
bemlshes. The rough disks for the crown
and flint lenses Of the Lick telescope cost
$4,000 each. They were ground to approxi-
mate shape with emery, polished with rouge,
and the final touches were added by rubbing
with the bare hand.
The best material for glassmaking is
sand is employed, being cheaper 1t is re-
duced to fine powder, together with an
aikall OF carbonate OF soda. At this stage
or the process the colors are put in, If COL
ored glass is wanted. For coloring the OK
ides Of various metals used Manganese
makes a beautiful purple and uranium
good yellow. Cobalt serves for blue, and the
black oxide of copper for green. The red
oxide OF copper makes an excellent red, but
the finest red is produced with Cassius pur-
pie, which is a gold compound. The glass
mixture prepared in the manner described is
melted in pot at a great heat 50 as to
make 1t limpid and to get rid of gases which
rise to the surface and pass off. Impurities
are skinned off of the surface The stuff is
then cooled down to temperature OF about
/ 600 degrees, when it is of ropy consists
ency and may be pressed or gathered on rods
for blowing.
SAND PAPER
What is called sand paper" is in reality
glass paper The glass used in its manu-
facture Is reduced to powder and sifted
through sheets of gauze of varying hneness
for different grades. The strong paper ems
ployed for the purpose is cut into big sheets.
NhlCu are SpIedu ana luVeneu down upon
tables. With large brushes the sheets are
then painted with a thin and even coat Of
hot glue. This must be carefully done, for
II the glue is too thin it sinks into the paper
and not enough remains on the surface to
hold fast the glass, so that the latter rubs
off. Finally wooden roller Is passed over,
to press the particles of glass firmly into
the glue. The sand paper" is now ready
for market.
Glass making is very ancient, dating back
a long time beyond the Christian era. The
origin OF 1t Is unknown, though various
apocryphal stories are current respecting its
discovery. For modern civilization to get
along without it would be almost as difcult
as to dispense with paper, which rivals glass
in respect to the number of patents for its
varied uses.
Strange Conduct of u Dog.
Mr.. William H. Richardson, farmer who
lives near Catonsville, has a Newfoundland
dog which was shot several years ago while
trying to bite man. says the BlltimOre Sun