New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1898-09-18

n
,nn iss,ed far centuries with the tables or nat
surfaces smooth aid mirrorlike. whit "' ,hc
or less frosted texture mas been b' ,' s. in
nnrtions i'm relief This is especE'IIS t'c CO .,an
"ntni" nhi.h have been struck as Specimen
pieces for ate" highly polished DIES IA. Zen
used for u certain time the an ~ ,c In re
the appcarance Of the tables ana inc Pai'S !" IN
IN, ic,n,rs ,ess and less marked. As is well
known. medals with polished surfaces ' a, ~
tarnish and blacken. NY cNpoSu'c W NV
ordinary atmospheric influences ~ tool,
sdortcd concurreniIy with the one Ju'' ~,
scribcd. Unpublished d!es ar, S n'adais struck
care is taken tp inipart to the n'cIii7 Tu
fron, them a dead ~ frosted surface ny Iupn."S
them with fine pumce Recently; d, 'nr ror,es
Mimi medals have been subjected 10 ,hr pr
known as sand blasting by the an , y, ~, If
nlianc, which projects against the SUI i't t,, -
the medal small jet Of AR. carry 'nS 80, $50
6nc sand and having 4 velocity ol ANU ,
INV nm ,'nr second when thus treated the sur
face Of the medal becomes minu'ely s 81 T.,
or frosted and may then be iurtn , "j is DARK
.aver,I WAYS Sometimes the surface IL VA
go hv axnosurc to an aqueous solution OF "
sulphidc followed by Rubbing WIN re, ~ s"I-
nur,i.r which removes the dark layer -, SUI /
ppbi%n rom The portions in high relief ana leaves
darl lines in the more deeply cut rcceS'cS.
II is however. preferable to cover wv on,J
with a layer of platinum ana ms 70 ,, ti ~
i',,nrs;pc il i'm An alcoholic soiuti"h VI
ci,,riJ. Of platinum until llackenen "rla't
IS produccd. Subsequent rupbihs WIN ., -
and very fine punlicc changes ti,c p 'O &c.,
anu - a delicate gray and II this operation
is conducted skilfully graduated shau '. ,hc,y
\, loft wherever the artist c'""'"'.
nrcscnce To be desirable. The leauty 81 i,
c. treated and the fidelity VIII VINO" ~
tails of the design arc reNeairu ar ,. w. DO
question. hut it may be douoIen nr",ecteJ
surface Of the medal is permanently r I So
medal with n frosted platinized surface ne,
however a great advantage over one 'erc,y
polished table. as the platihz,n '', na a,mnsnhcrc
decuencd in tone 10y cXPosur" I" ,''' 'n,ri l.,
ana rnlikr medals which have been s s ~
the ordirary way. does not BOONE ui ,.iao,
nv hlntchcs ~ tarnish. The ho"ten P'uint,
he.
freshness hy careful rubbing with Sott I't r
while a polished silver one cannot pc :" I
vatcd the tarniSh a't"'h" VI"
DESTROYS the polish. g., ,t, i, tho
during the last year. for the hrst 'ii," ~ , 49,.
history Of IN" British Mint ''iei ., a,r,,rrs
issued with frosted ana pia'ih'1'u a,tr.r
Mo,e than twcnty-sev thousand larer "',t,'
medals vcr, platinized by slight n'pli'loHs .,
~ the above method. IT became h''rSSi,,,
:. ' w" =, nrnvi T., AN appliance for producing
tb. sand blad and this. together WIN a Si'i
one horsepower motor for DRIVING 1t. Lis nrr"
Gttcd UP in the basement OF Inc Assay 'P"'
Medals Of bronze differ considerably from
thcsc Of silver. as their surfaces air l'' "''l'
liable 10 be innuen' cd either Dy thc SOW "l'
,ta, -, IN. constituents Of the atmosph'f" oi
by the moro rapid action 81 chr"', h;.h ha,c
Ancient silver coins for instance. NJ" ,
boon long buried in the earth 30 not shp" any
. ov, IN Nv. So wide A range ~ color in their
na,ina or crust IA Is revealed on Guns W ~ -,
bronze copper which have pe'h n'' ,,, st,ycr
same way This is due To IN" tact INA, wv,
is FAR Less affected. than copper ~ the 'n'',u'
action ~ the constituents OF SOILS or % a'''''
pheric influences.
TIE PATINA VALUABLE
The ratina acquired by An ancient com ~, -.
medal often constitutes no rhaii par n.,
value 'You would laugh nj me. saln rnn
ander In Addison's charming daI"su"s u'",
tho usefulness OF ancient medals. shouiu
mako YOU a learned dissertation on the nature
OF r,,sts shall only tell you that there are '"p
or three sorts OF them which are extremely
heau,if,, in the eye Of the antiouary. and pre-
inc
nish The object Of the medailist ~ accurately
EXPRESSED in the above sentence. Tor ne en-
dcayOrs to protect the surface OF AN "enaS !"
which copper ~ the man conSt'uen' W
na,ina or film Of oxide. 80 as to preserve the
medal from further change. This may oe
effected in various ways. The incdas OF l'i,
Italian Renaissance were not Slru'h. pu' 90
by the method Of cera perduta' ahn h'u ',,, ~
the beauty of the medal due To the SKIN
mr. peliicie OF oxide which the medal acquired
during casting The skill Of the ARTIST III arrah6
ing the composition Of the bronze anu hNHE
the temperature at which 1t was cast was re-
vcaIed in the texture Of the medals surface
In rpodcrn times most medals to which the
name Of bronze is given are really OF copper
"bronzed" or colored artihcially on the surface
The process by which this coloring Is eHcc"n
has long been employed. and Is mus d'ScrlDcu
I'm An old recipe: Apply with brush 10 the sur
face of the medal common crocus powder. JEW
ellers' rouge. previously made INTO Sh"u'n
paste with water. When dry expose the ne'iai
over a clear fire for about minute laSty
when the medal ~ sufficiently cold. p0sh IL
with u plate brush. The exact composition OF
the superficial layer Of oxide which Is formed
has | believe. never been asc"rtained; nut IL Is
we'll known that the tint varies greatly from
iicbt brown TO deep chocolate according to the
particular variety Of oxide OF iron which ~ usch
With a view to ascertain whether TINS Ga
method could not be replaced with advantage,
Il was natural to turn to the work OF Jitaiir'e
b, mag