M. TECHNOLOGY. 497 



ABYSSINIAN GOLD. 



A new metallic compound, which bears the somewhat fan- 

 ciful name of Abyssinian, or Talmi gold, has lately been 

 manufactured in large quantity in Germany, for the purpose 

 of fabricating imitation gold jewelry and other objects. This 

 is a brass composed of about 91 parts of copper and 8 of zinc. 

 The appearance of gold is obtained by causing ii very thin 

 sheet of gold to adhere by passing it through rollers. This 

 gilded sheet is then cut and formed into ornamental articles 

 by means of ingeniously constructed steel instruments. 18 

 A, April 19,1872, 133. 



METHOD OF WELDING COPPER. 



According to a quotation in the Journal of the Franklin 

 Institute, Mr. Rust has invented a method by which he ac- 

 complishes the most perfect welding of copper. This con- 

 sists of a mixture composed of 358 parts of phosphate of soda 

 and 124 parts of boracic acid. The powder is to be applied 

 when the metal is at a dull red heat, which is then brought 

 to a cherry-red and at once hammered. As the metal is very 

 apt to soften when exposed to a high degree of heat, a wood- 

 en hammer is recommended. All carbonaceous matters are 

 to be carefully removed from the surfaces to be joined, since 

 the principle of the operation depends on the formation of a 

 very fusible phosphate of copper, which will be reduced by 

 the carbon to the state of a phosphide. The phosphate of 

 copper dissolves a thin film of oxide on the surfaces of the 

 metal, keeping these clean and in a condition to weld. 1 D, 

 January, 1872, 8. 



IMPROVED MANUFACTURE OF RED-LEAD. 



The ordinary process of the manufacture of red-lead con- 

 sists in exposing oxide of lead, or litharge, in trays in the 

 same furnace that serves for its production ; but this method 

 is very tedious and uncertain in its yield, owing to the 

 changes of temperature to which the substance is exposed in 

 the furnaces. The most important element for a successful 

 result, next to the access of sufficient air, is said to be con- 

 stancy of the proper temperature, as the temperature at 

 which litharge takes up oxygen and that at which the red- 



