INDEX.

Extraction from large proportions of

H-on-168

Means of readily discovering it when

dissolved in acids-102,1 10

Distinguished from other yellow me-tals -123, 184

Very minute quantities in minerals, intome circumstances extracted to ad-vantage -164

Not separable from copper, as silver is,

by eliquation with lead-167

Separation from gilt works-1 63

Gold, use of mixing alloy with it — j i 4

Metals fit for its alloy-1 1 5

English standard gold-1 j 6

Crown gold-117

Way of accounting its fineness in diffe-rent countries-11;

Fineness of different coins — 116, 117Latitude of fineness in the English coin-age — —-11 6

Its proportional value to silver in diffe-rent nations---11 3

Gold, of judging of its fineness from its

weight-125

from its colour on the touch stone 119

Assaying of gold-127

"Refining of gold on the test-144

by aquafortis-—-.147

by cementation-154

by antimony —- 156

by vitriolic acid — — — — 95

by vitriol —- 159

Purification by nitre--68

by sublimate-70, 94

Different means of purifying it from pla-sma ----—-590

Separated from base metals by calcination

and amalgamation —-— 89

Means of avoiding imposition in the

Chinese gold trade—-124,126

Purification from emery-147

Gold, Recovery of its lustre when sullied^Its colour heightened—— — 83,68

Made pale-68, 78, l r 2

Observations on melting it-67

Marks of its fineness and toughness in

fusion-—-69

Of preserving or restoring its toughness

-67

Whether black-lead crucibles injurious—__—_ 616

Solders for it-—-81,617

Its great ductility, and the arts depend-ing thereon -44.

Expansion by heat- 42

Degree 0! extension in wire and leaf 59

Experiments of its gravity-41

Variations of its gravity from heat and

cold---— — 42

Difference of its comparative weight tobrass in heavy and light air — 43Said to be vitrescible by large burning

glasses-70

Examination of this account — — 71Changed purple — 74, 105, 107, 108

Amalgamation with mercury-75

Mixture with different metals-82

Melted with different proportions of

platina- 525

Not always diffused equally through

other metals- 86

Separated from silver by fusion — 86Its habitus to different acids, &c. — 90

Dissolved in the nitrous acid-gg

Dissolved in the marine acid-94

Corroded by phofphorine acid —- ,14

Solution in aqua regia -96

Crystallized-93

Volatilized-100

Recovered after volatilization — 101Separation from acids by inflammable

liquors — — ■— —-ior

Precipitation by alcalies —-104

Dissolved in volatile alcali-rc-f

Precipitation by metallic bodies— 108Dissolved by hepar fulphuris — 111Recovered from thehepar— 111,112

Gold, enquiry into its producibility and

destructibility by art-199

Debalements and augmentations^ of it

Gold, white, see Platir.a

Gtld beaters skin, how prepared-46

Repaired when grown unfit for use 47

Gold powder -63, 76.99, 109

Gold-JIze, for gildingfor varnish-

-63.

369 1

Gold coloured metal-213, 624

Pigments — —-222

Glasses — — — — — — — 626Varnish or lacquer — — —223, 624Pp p p 2 GranuUtha