Idaho semi-weekly world. [volume] (Idaho City, Idaho Territory) 1875-1908, 1889-09-03
Platinum. the den..st Of n. oro,t,a,,

=
Platinum. the densest Of the ordif,or, (
metals. Possesses a very high point OF |
fusion. The metal fuses only in the
heat OF the oxyhydrogen blow-pi |
When In the state OF very fine wire 1t
may be melted into small globules by
the heat Of an ordinary mouth blow.
pipe, and Is quite readily fused in very
small quantities by the aid OF not
blast supplied To All ordinary Bunson
gas name. Platinum belongs 10 tho
class OF metals which soften before
they attain perfect huidity, This pc
c'lllarity permits the uniting OF plati.
mum surfaces without the use OF solder.
and enables the finely divided metal,
Technically termed the '.metallit
SPONGE TO be wrought into a solid
and compact bar. Platinum is no.
volatile ut any temperature we are
able to command. though doubtless al
sufficiently high temperatures it. In
common with all substances, would be
vaporized. Platinum does not con-
bine directly with oxygen. and there
fore does not waste during the process
OF melting.
Gold mclts at about 2.0i6o to 2,t90o
f., according to different authorities
1t is affected neither by water nor air
at any temperature. and it is not at
tackled by ordinary acid. 1t is the ros.
malleable OF all the metals. and may be
| beaten into sheets Of surprising won
derful thinness. Its very great mallea.
bility renders it unfit for use for jewelry
or for coinage until its hardness and
| consequent durability are increased by
alloying it with silver or copper. Elk.
posed to the heat of the oxyhydrogen
blow-pipe it is known to be vaporized
and it was formerly supposed that il
was not volatile at lower temperatures
but the researches of Napier ant
Makins show that rehabilitation occur:
at temperatures Of an ordinary muffl'
furnace when alloys of gold and silver
are cupelled with lead. An analysis o
deposits taken from the chimney of ;
small reverbatory furnace, in daily us,
for cupelling gold for months. showed
fourteen per cent. of silver and 7.
grains of gold for every eight ounce
OF silver. Still. after the destruction o
a quantity of jewelry by fire, grea
proportion OF the gold should be re
coverable. since but a small quantity
il any, would be volatilized Gold will
alloy readily with nearly all othe
metals. Its alloys with silver an
copper are. however, the only one
employed in the arts.
, Lead melts at about 600
Unlike gold, it combines readily wit
the oxygen OF the air, forming variou
, oxides. mainly litharge, product {
the direct oxidation OF the meta
When melted and exposed to tn
: atmosphere it absorbs oxygen yer
, rapidly; so that. unless caution be e,
: ercised in melting, it is apt to vast
> from direct oxidation. and especial
q from the fact that at white heat
, boils and voatilizes. When in vel
= finely divided state. metallic lead cor
4 bines so rapidly with oxygen that
+ takes fire while falling through the al
!, and burns with ID livid flash. Th
:. metal possesses the valuable proper
t OF welding in the cold, provided Il
O surfaces joined are clean and free fro
y oxide. Lead forms alloys with mai
!, of the metals. Many of its alloys a
l. OF great value. 1t alloys but impe
q feetly with copper, zinc, nickel al
9 iron, though by Introducing thi
# metal having an affinity for both Il
. others. this difficulty may be ovcrcon
d The following are some of the impt
t.. tant alloys:
If Soldiers -Lead alleged with tin forr
e various soldiers. Fine solder contai
ID two parts of tin and two OF lead; co
le mon solder. equal parts of tin and lea
Is coarse solder contains two parts OF lie
IN and one OF tin; plumbers solder Is I
same as the last.
Pewter is composed OF eighty pa
OF lead and twenty parts OF tin; but
ID these copper, antimony or zinc Is g
OF orally added. Lead dlloyed with
h. and bismuth forms a variety of allo
Il. that are remarkable for their extra
n binary low melting points, on whl
~ account they are termed fusible meta
IS. Roses fnsibe alloys. formed OF /
lis parts OF muth. one of tin and one
ut lead, me is al about 203 . f., or bel
ch the boiling point of water. Britain
NIB metal is an alloy of equal parts
is, brass tin. antimorv and bismuth.
g, Silver melts at about 1882 f., or
n about bright-red heat, Like gold
OF is not attacked by air or moisture,
IN, tarnish which appears on sllverw
ed being caused by gases in the air
co Blacksmith and Wheelwright.
at