2go

Hydrostatics.

Gravities of an equal Bulk of the respec-tive Fluids; and consequently, they may

thus

only will sink in Mercury; therefore by weighing Goldin Mercury and Water, the specific Gravities of thesetwo Fluids may be determined by the Hydrostatic Ba-lance : But since Mercury will readily adhere to Gold,it will create us some Trouble in getting it off again,which must be done by Fire, or Aqua Fortis j as thelatter is not always at hand, it is common to put Goldinto the Fire, but Care must be taken not to put it intoa Coal Fire, because the acid Spirit of the Sulphur willlest'en the Cohesion of the Particles of the Gold, and sorender it very brittle, and apt to break, especially whenlaid on a cold Stone to cool ; the best way therefore tofind the specific Gravities of these Fluids is that abovedirected in Art. 13.

16. AT ABLE of SPECIFIC GRAVITIES.

Of METALS.

Fine or pure Gold,

19,640

Gold of a Guinea of George II.

17,150

Gold of a Moidore,

1 7 , 1 4 °

Silver fine or pure,

11,091

Silver of a Shilling of George II.

10,000

Lead,

10,130

Copper,

9,000

Brass cast,

7,850

- wrought,

8,000

Steel tempered,

7'704

Iron,

7'645

Tin,

7,550

17. MINERALS , ORES,

(Ac.

Copper Ore,

3,775

Lead Ore,

6,80s

Bismuth,

9,700

Turbith Mineral,

8,235

Antimony from Germany,

4,06s