The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1853-08-30

Il
ash, and that the latter is properly cleaned and {,
cnss, as the charcoal has she nect Of weaksnii
The metal oxide. II is also requisite to use gre
deal OF caution in the degree Of heat applied, q
color OF the glass depending not only ON thesqua
ties Of the oxide and glass, hut on the tenperatu
and time Of melting. In order to test their sevel
conditions, u Is usual TO try n snan quantity Of I
! mixture in the same relative prop rions Grst. n
only by repeated experiments Il this SORT ia,
exact quantity Of the oxide 10 be used and ths thi
ness OF the glass can be determined.
Blue glass Ia m idc by the aGmixture OF oxida
cobalt to the fused materials. rh'5 color 10 perm
nent at very high Temperatures, aud u.s. thersiors,
invaluable article In the msuuIa sure Of porecl
and pottery as well as OF glass W1en fused \
the latter il communicates beautiful blue tint, vi
out imparing its transparency; and tho glass
be made as light or As dark As Teguired BY ths gu
! tity Of color used A proportiou VI about hve
cent gives . very fine blue. For tbs finese desa
tons OF glass, none but the ceaaest oxide u u
Although crystal glass IS sometimes used for
BILE. In employing the latter portion Of oxide
iron must be mixed with the cobet II little
gaDese be added 70 the cobalt il g,ll produce M
| full violet.
Yellow glass can be proauced In two ways
the addition either Of oxide of SILVER or oxide Of
mony 10 the glass mixture. For coloring with
| yer, the clear white lead glass j. The besS WIN
contains few per cent Of argl linle color nay
added. For cOlOriBg with the OXIDE Of antim(
mirror glass Is usually employed The variation
color, nom IN excessively light 20 sdark TINT are
tanned by the admixture Of small quantities Of q
coal; but in these cases. the only glass that can
| used is the common clear lead glass; and care IL
| be taken that the glass mixture does not o0Iz
either arsenic or saltpetre. Ii gold tint b reqd,
about one per cent Of oxide Of manganese rsae
| added.
Green glass is made by the Introduction o's
oxide OF copper, in the proportion Of IA 70 n
cent, or by the addition of common verdigrs, VI,
is dried beforehand, pulverized. and mixed witls :
| glass. By the addition OF a Stlo zatfre, or cot
| a1Onn the N will bAcOInn liz mr.
quired. The green can also be produced by ,
mixture Of the oxide of cobsi5. III pr0pM t,0n
about per cent, and that Oh the oxide Of antimV
in the proportion Of per cent The oxide1,
chrome is occasionally added
Red glass is made In several ways, the prlneis
Of which ID by the use Of the oxide Of red eopE.
For this purpose copper filings .re generally q
| ployed being calcined in crucble until they
come brittle enough to red ice powder. Co
must, however, be taken not to oxidze them n
much, az they would therebyimpart greenish kss
TO the glass. To the oxide thus prepared ABOUT 10
same proportion Of tartar must % added and TIM
mixed with the glass in the proportion (fOr comma
az well as crystal glass; OF from 70 Ir
cent. II the oxide be added T. the already Heiid
glass mixture, it will only be necessary u putin
about One-fith per cent OF it 10 produce the III
color. This wili inpart dark purple or blush ri
color 70 the glass; Lighter tluts cannot De obaind
with postiveness, because the strength VI the cool
is so great that the least quanti OF the oxide viii
produce a very dark color, aud II exposed h
The glass mixture must therefore, be quite ket
from al acid materials, such as senic, manganese,
and saltpetrc. Ii the oxide encounters any Of thek
ingredients during its fusion, It will become o +,
dark green color, but by adding little charcoal
and tartar TO IT, and stirring II with stick, II nay
be brought back to it's original tint As the glaa
in cooling, is liable to lose part OK its color, iti'
necessary to heat the place where it is worked q
certain Temperature; the addition of little oxide "
tin will also help to counterfeit tde modReah0Ok o
color to which It is subject from exposure TO cooe
atmosphere. There Is this advan age IN using cr1s
tai glass for this color that it coos more slowly AZ
enables the workman TO com iete the article win
out again having recourse to the furnace. II n
tint required be brighter red or scarlet, 1t wnb'
necessary to add to the glass mixture two per cen
Of its weight Of oxide Of tin, and oneffsh per en-
OF oxide Of iron. When melted, one fifth pcr,seAt Q
oxide Of copper will complete the process. FH VI
purple color sulphur OF copper l. substituted for thu
oxide, with, Of course, che sams quantity q e1id
OF iron. Although the purple glass made with ol1d
of copper il too dark TO be Transparent this defec
is in some degree remedied, and some beautiid
effects are produced by laying on coating Of Whit
glass, and then cutting either partially or who'll
through the purple glass, SO - to obtain . vaylet
One Of the most delicate and costly processes, how
ever, in this manufacture, IL the making OF rub
glass The cOloring ingredient - the oxide Of gols
combined with the oxide Of tin. The uncertainty 4
tending the results and the los consequent on fau,
continue to keep up the price Of articles made Of il
Us only small quantities can he manufactured al
time. Some idea may be formed OF the cOlOrin.
power Of the oxide Of gold from the fact that q,
perceptible rcd The usual mode Of manufseture
by mixing the fine powdered glass with the coloin
preparation in the proportion Of to 4; after The
are fused, the MIXTURE which has now become Of
yeiOwish tinge, rs thrown nto the water 10 cos, a
the same operation s gone through at least six time,
until the glass assumes a beautiful ruby Nm
portion OF manganese may he added to pr0ilao
the different shades, but If violet Is wanted . sns
| 0uantitu If cobalt uuct Ia univ cd uUi<h
Brown ID only Q modification of the latter c0l6l
obtained by the addition Of the sixth part Of Lsr
to IL.
Black glass is produced by the admixMre Of ~
6cient quantity Of manganese and Zafe, ef mangs
nese zaffre, and oxide Of iron, or again, Of Uangs
nese zanfe oxide Of iron and oxide Of copper, WIT
the glass
The untrnnsparnt white or opal glass can We mad
either with oxide OF tin or bone earth.
From some cnriOos experiments that have bee
made by French chemist, it would appear that q
the cOlors OF the prisDatic spectrum may be impair
ed to glass by the use Of the oxide Of iron, in sS
ing proportions, and by the agency OF different IL
grees Of heat, and that all the colors are produce
p their natural disposition in proportion as the VEN
iIraIpre is increased. He explains the modification
that take place in L.. annsaDg oven BY the agency
light, and is doubtful whether any cnahkM in
oxidation OF the metal will explain the pah0togcni
effect He is disposed to attribute these shrurnati
changes 10 some notifications OF the sOmposin
PARTICLES rather than 70 any chemical changes in th
materials employed.
We have not thought It necessary to enter into an
details respecting the moulding and cutting Of til
glass, these processes beiong to the ordinary 70,
tine Of the manufacturer, and are too generally Ut
dersto0d to require explanation.
Some notion may be formed Of the extent and I'M
p0rtancc which this branch Of industry has attane
in Bohemia, from the following return Of her es
ports for one year, (lS4O:-
Hollow sndtsbis &c o45 ewt valued at 3004 coo6
| Cut and eat crystal glass
ard mirrors $1,000. .le,0 or g 1892 2oo1
Besds artihb gerns &c. 5,2l 7s3,d00f
rs 2s3 1000, 0o0f
The glass and mirrors produced in Bolemi
amount annually to more than double the sum OF be
foreign exports, and may be estimated at maximah
value Of ten and half millions OF forms. The fine
descriptions Of glass arc also manufactured in tn
Venitinn Provinces Upper and Lower Austria, an.
lombardy bat witk the exception Of the first named
these countries do not produce themin quantities sa6
ceDt to meet the home demand.
Tho principal glass msnufa stories OF Bohemia ar
those OF Count Won Harsch, at Eev~elt; Conn
Buquoy, at ScbwartZthal and Silb6rberg; Jankc
Brothers, at Blottensdor; Meyers, Nephews, q