242 (.oi. n. 



the sulphate of iron, and many other substances, cause its precipi- 

 tation ; ether however, speedily redissolves it, forming a solution 

 which is used for coating metallic substances with gold. If gold 

 be heated in chlorine, in a state of minute division, a deep yellow 

 coloured compound is produced, which, when Dissolved in water, is 

 a chloride of gold ; and by adding a solution of potash to the 

 chloride, a precipitate is formed, which is oxide of gold. If a plate 

 of tin be immersed in a solution of muriate of gold, a purple 

 powder is thrown down, which is much used for enamel painting, 

 and for tinging glass of a fine red colour, a compound generally 

 known as the purple powder of Cassius. The ethenal solution of 

 gold, or aurum potabile, which was at one time given internally as 

 a medicine, is an inert compound of nitro -muriate of gold, ether, 

 and some essential oil. 



Salts of Gold. 



Metallic gold has no action on the human body ; but some of 

 the compounds, more particularly the chloride of gold and soda, 

 have been occasinally used in medicine. The Salts of Gold are in 

 general formed by digesting the oxides of gold in the acid with 

 which they are to be combined. 



Chloride of Gold. — This is a compound of chlorine and 

 metallic gold. Tt is prepared by dissolving pure beaten gold, cut in 

 small pieces, in nitro-muriatic acid ; concentrating the solution by 

 evaporation, and then setting it aside to crystalize. The solution 

 affords small prismatic crystals of a beautiful ruby-red colour ; 

 but they are so deliquescent, that they can only be preserved in 

 close-stopped phials. The taste is astringent, and very disagreeable, 

 and acts when taken into the stomach, even in very small doses, as 

 a local irritant and corrosive poison. Three grains of the chloride 

 injected into the veins of a very strong dog, occasioned the death 

 of the animal ; and the lungs were found, on dissection, so gorged 

 with blood as to sink in water. The chloride of gold is regarded as 

 a powerful stimulant and antisyphilitic. As an antisyphilitic it 

 was employed as early as the 16th century, by Gabriel Fallopius ; 

 and it has been lately much extolled by M. Christen, in scrofula, 

 bronchocele, herpetic eruptions, scirrhus, and even in tubercular 



