Evening capital journal. (Salem, Or.) 1888-1893, 1891-03-03
FACTS ABOUT MARBLE.
How the Rugged Rock u Converted Int
Polished yariegated slabs.

feW people VINO hNdhA pSAOiN q hAi'D''
monument or mantel, or even soda water
fOunt in a drug store, and admire the hlgh-
ly.polished variegated marble, says the New
York Commercial 1dpedtser, realize the
amount Of time and labor that has been ex-
pended in the evolution Of the completed
structure from the raw materials. Inc
highly-colored varieties are found chiefly ID
Italy, Spain, France, Belgium, or Portugal
though sometimes in Mexico or Algeria
The white stone Is common IN TINS SJsle'
Among the marbles which most frequently
enter into composition Of fancy apparatus
are: ,., 49,.
Italian-white, vernal and cloud"d- with blu
ish gray: Etruriau-pure porcelain white sara
gossa shaded cream white, Veinei W.th uarN
gray: Algerian and Mexican OnyN-transluceht
viii u, veined with OPAQUE white, Low, or
pink k:Bardigllo--delicatey veined gray 'barfah'
colin-shaded pearl gray, dashed vita earn /
ian red; Sicnna-gOldon yellow, clouued WIN
white and yeinod with olive and brown; Ten
nessee-choco' ate, frosted with white; Ge %
green: Brocatel-rchly mottled, yellow, pur-
ple. brown, white and red; Violet B-ocatel-
purple mottled and veined with golde y2NyW'
L sbon-fedd sh; GryOtte Of Franc deep REQ,
shaded IN red aud brown; Cryot9 fleurc-
purplish rcd, mottled with pearl white war
wick brilliant red yeincd with white; Bel
Rlan-velyely black; African 90 yellow, " IN
.
yille-grayish PINK, with light blue ycinHg,
The colored marbles retain their fresh
ness longer and can be repolished after
many years use.
The marble is extracted from the quarry
in obong blocks cut out by means OF
wedges.
Except when designated for statuary or
building purposes the first thing the manu-
facturer does Is 10 place the block OF marble
under q gang-saw in order TO saw II INTO
slabs. Tho gang-saw consists merely OF
series Of parallel saws, to which an oscllla-
ting motion Is impaired while they are Kept
fed with sand and water. When they come
from the gang-saw the slabs are generally
about N inches thick, so that they may
dress 10 one inch when rubbed on both
sides The slabs are then inspected. To the
inexperienced eye the rough slabs are much
alike, and while the good qualities Of the
slab are only fully brought out under the
polsher's mop, the imperceptible defects
are also magnifed very much 1t is there
fore necessary 10 detect flaws before the
polishing beg rs.
The perfect slabs are cut into required
lengths by rip-saw and passed to the rub
bng bed 10 be rubbed smooth. The rubbing
bed consists Of a solid horizontal castlron
wheel about four inches thick and usually
about twelve or thirteen feet in diameter.
This wheel is fixed in vertical shaft which
reyolves on two chilled steel friction balls,
placed one upon the other, and mclosed in a
cast-iron box which is kept well supplied
/ with oil The box itself is firmly imbedded
/ in a stone foundation, aud the entire struct
/ ure is made as true and as steady as pos
| sible. 1t requires a great deal Of care and
attention to keep the rubbing-bed perfectly
] i L.. taTNt n Ia
! il down ror a whole week with bluestone in
| order TO keep the surface smooth.
when the slab leaves the rubbing-bed IL
/ is comparatively smooth, and is ready to be
cut out by hand into its final shape. 1t then
passes into the hands of the polishers, who
are provided with rubbers made OF ordinary
! ticking rolled up into Il mop Of about three
or four inches in diameter and sewed hrmly
4 through and through. With these they rub
the surface OF the slab back and forth, hour
after hour, until they bring out the high
polish 80 much admired. The marble is
urst rubbed with grit, tnen with pumice
stone, and then with hone. On some white
marbles oxalic acid is then used, and finally
the finishing touches are given with putty
OF zinc. On colored marbles emory anC
French putty, prepared with sulphur ant
loud, are used. 1t is estimated that eacl
square foot Of surface polished costs ont
man four hours Of steady work.
In gliding, four or five gold leaves ar,
blown into cushion made of board GOV
cred with chamois. The glider cuts it int
strips quarter OF an inch wide, lays It OF
the marble with his "tip,n then "cottons
IL on, after which he rubs II down with
fine hair brush in order 10 smooth the lap
and form an even aud continuous surface
, He then cleans of the edges with cutie fish
Great dexterity is acquired by gilders, anS
they seem 10 handle with the greatest eas'
the delicate gold leaf which the slghcs
breath OF air is sufficient 10 carry or, auC
which In inexperienced hands Is utterly un
manageable,
The variogated, dark colored marbles ar,
most expensive, but they are also generally
harder and more durable, as we'll ds NOR,
beautiful, than those that are white or hgA
colored The common white marble, who,
Is not 80 valuable from an ornamental pom
Of view, has n separate value ns beng th
best basis for the production OF carbonl
acid gas for the manufacture Of 80 soda WA
ter and all other oarOunatcd beverages, aAt
large trade is done In II Tor this purposc
IL has succeeded whiting and biclrbunat,
OF soda In this respect ON account ~ IL
cheapness A barrel OF good marble .dUst
!
equal quantity Of whiting costs about S3 ~
and produces no moro gas. 4 like weigh
OF bicarbonato OF soda produces doubl
; amount Of gas, but costs about a.
( As far as chemical composition is con
cerned marble and whiting are analogous
both are carbonates Of hme aud whel
equally pure both contain the same amour
Of carbonic acid Whiting, however,
rarely, II ever, as pure as marble. IL con
sists chiefly OF the remains OF eNtrcmor
small anlmalculos