Page 217 - My FlipBook

GOLD. — —— 205

well Stirred with a plalinuni rod and poured into the ingot
mould immediately.
J'^)rmula No. i of the following" recii)es is a fraction over
fifteen carats tine; No. 2 furnishes a solder eighteen carats
line; and No. 3 a solder tw^enty carats fine, for crown- and
l)ri(lge-work.
Formula No. i. Fonnula No. 2.
6 dwts. gold coin, Gold coin, 30 pnrls.
30 grs. silver. Silver, 4 "
20 grs. copper, Copper, i "
10 grs. brass. Brass, i '"
Formula No. j.
Pure gold, 5 dwt.
' copper 6 grs.
"
" silver 12
"
Spelter solder, 6
Method of Ascertaining the Carat of any given Alloy.*
—The proportion may be expressed as follow^s :
"As the weight of the alloyed mass is to the weight of
gold it contains, so is 24 to the standard sought. Take,
for example, Harris's No. gold solder :
3
Pure gold, 6 parts.
"
silver, 2 "
" copper, I "
Total 9 "
—
" The total ])roportion would be expressed thus :
9 : 6 : : 24 : 16.
"
From this any one can deduce the following :
" Rule.—Multiply 24 by the weight of gold in the
alloyed mass and divide the product by the w^eight of the
mass ; the quotient is the carat sought.
" In the above example 24 multiplied by 6, the quantity
* From an article on " Alloying of Gold," by Prof. Watt.