GOLD. ITTf 



lace-makers it is still thinner. An ingot of silver, usually 

 about thirty pounds weight, is rounded into a cylinder, an 

 inch and a half in diameter, and twenty-two inches long. 

 Two ounces of gold leaf are sufficient to cover this cylinder, 

 and sometimes it is effected with a little more than one. 

 The ingot is repeatedly drawn through the holes of several 

 irons, each smaller than the other, till it be finer than a hair ; 

 and yet the gold covers it, and never leaves the minutest 

 part of the silver bare, even to the microscope. It has been 

 calculated, that it would take fourteen millions of films of 

 gold, such as is on some fine gilt wire, to make up the thick- 

 ness of one inch: whereas fourteen mi41ion leaves of com- 

 mon printing paper would occupy nearly three-fourths of a 

 mile in thickness. The ductility of gold is such, that one 

 ounce of it is sufficient to gild a silver wire more than thir- 

 teen hundred miles long. 



Gold may be disisolved in nitro-muriatic acid ; and it thus 

 becomes muriate of gold, which is obtained in small crystals, 

 and is very soluble in water. If white satin riband, or silk, 

 be moistened with a diluted solution of gold, and, while 

 moist, exposed to a current of hydrogen gas or sulphurous 

 acid gas, the metal will immediately be reduced, and the 

 silk become gilt with a regular coat of gold. The potters 

 dissolve gold to be applied to the common kind of porcelain, 

 and it is used in a state of solution for staining ivory and 

 ornamental feathers. It gives a beautiful purple red, which 

 cannot be effaced ; even marble may be stained with it. 

 Mercury and gold form a compound called the amalgam of 

 gold, which is mucli used in gilding. The amalgam is 

 spread upon the metal which is to be gilt ; and then, by the 

 application of a gentle and equal heat, the mercury is driven 

 off, and the gold left adhering to the metallic surface. 



Questions. — 1. In what state is gold found ? 2. Wliat is said of 

 its weight and tenacity ? 3. How do gold-beaters extend it ? 4. 

 What surface may an ounce be made to cover ? 5. Ho\y is silver wire 

 gilt ? 6. What calculation has been made respecting the films of gold 

 on gilt wire ? 7. What length of silver v/ire may be covered with an 

 ounce of gold? 8. To what uses may muriate of gold be applied? 

 9v What is amalgam of gold, and how is it used in gilding ? 



