, 1858-05-21
PUGET SOUND HERALD.
srEtLAcooM, ", T., MAY 81, 1858.
Gbidi IT'S Chemistry and Geology.


at1 From the Family Friend5 - s.sH. .i.H
On all sides do we hear intending emigrants
eagerly inquiring for the best way to tell gold
or sec them, from the works Of our geologists,
endeayofing to ascertain the most favorable local
tiles for finding it Chemistry and mineralOgy
can answer their first and practical geology their
second question.
Often have we had Jumps Of copper and iron
pyrites brought to US with the request "WOuld
you be kind enough TO tell us whether this is
goldg" and often have we smiled at the ludicrous
change Of countenance in the inquirer, as we as
sured him that the fancied treasure was nought
but sulphurct Of iron.
God is the only yellow metal, and is always
found in metallic state; rarely pure, and always
presents the yellow character which belongs to it.
When piece Of iron is left exposed to the
action Of the atmosphere, it becomes oxidated, or
rusts, and rust is oxide Of iron; gold, however,
does not tarnish when exposed to the air, on ac-
count Of its feeble affinitics; and can be melted
and kept fluid without change for any length Of
time. ia
We have, however, seen gold burn, which It
does with q greenish fame, when exposed to q
strong electric OF galvanic spark
Gold requires strong heat to melt il; 2S40
deg. Fahrenheit being necessary for that purpose.
To talk Of gold steam may appear extraordinary,
yet it has been discovered that when in state
Of fusion il is to a small extent converted into
tapOr.
The extreme maleability Of gold is well
known; and here Is one test by which It can be
distinguished from iron and copper pyrites.
Give tho mineral or rather little Bit Of Il, q
smart rap On hard Substance, with hammer I;
And II itbe gold you viii merely fatten Il little;
but II either Of the two above-named substances,
Il will smash into little bits Indeed, this test
applies to the smallest atom; for scale Of gold
can be picked up On the point Of needle
which cannot be done with the s6lphurct Of
either iron or copper Again. gold is not acted
upon by any single acid, but when nitric and
muriatic acids arc mixed, they detCmpose each
Uthep producing chlorine, and nitrous acid and
d mixture Of these two acids, called ntro.muria.
tic aSid, or aqua Tegid, has the power Of dlssOvs
Ing gold
IL hcweten we take copper pyrites, we shall
find that when dissolved in acid, II a knife-blade
be dipped in the solution, il will be covered with
a precipitation Of cOpperi or, If we take iron
pyrites dissolve 4 in spirits Of salts or muriatie
acid, in which We have put a few drops Of nitric
acid, and then add little prussiate Of potash we
viii get bright blue precipitatc, which is Prus-
sian blue.
Perhaps as casy test for gold as any is, when
It Is dissolved in aqua reCia, to add chloride Of
tin, on which purple prccipitate win be thrown
down
The following are tho directions lately giyenby
DIR. Lyon Playhir, for examining mineral to
ascertain whether Il contains gold: "Supposing
you have an anuieEeus qaartz, reduce Il to pow
der aid boil with aqua nsgia. A1er dluting il
with water, pass tho solution through alter,
allow Il 10 cool and adda solution Gf carbonate
Of soda, until itceAses to ciervesce Filteragain,
and add oxalic acid until the etIervescennece ceases
and 1t tastes sour; then bOii and il there be any
gold present Il will DO precipitatsd as black
powder"
In.additiOn 70 copper and iron pyrites, how
ever, there is smother substance, totally unlike
gold, but sometimes mistaken Tor i; It is called
yellowlmica, and may be easily known from
gold BY its ncnmetalhc lustre, its toliated struc-
ture, It's low specihe gravity, and the harsh
scraping noise made whom kniie-point is drawn
-overit Gold has powerful affinity for mer-
cury, andahis property is made use Of to collect
small particles Of gold, 1npreservable in any
OthsrwAy. When the mercury has gathered up
the gold, they arc easily separated, because mer-