100 ALLOY 



Six ounces lead to ono pound copper is the ordinary pot-metal, called dry pot-metal, 

 as this quantity of load Trill be taken up without separating on cooling ; this alloy is 

 brittle when warmed. 



Seven ounces lead to one pound copper forms an alloy which is rather short, or 

 disposed to break. 



Eight ounces load to one pound copper is an inferior pot-metal, called wet pot- 

 metal, as the load partly oozos out in cooling, especially when the new metals are 

 mixed ; it is therefore always usual to fill the crucible in part with old metal, and to 

 add new for the remainder. This alloy is very brittle when slightly warmed. More 

 load can scarcely be used as it separates on cooling. 



Antimony twenty parts and lead eighty parts form the printing-type of France ; 

 and lead and antimony are united in various proportions to form tho type-metal of 

 our printers. See TYFE-MBTAL. 



Mr. James Nasmyth, in a letter to the 'Athenaeum' (No. 1176, p. 511), directed 

 attention to the employment of lead, and its fitness as a substitute for all works of 

 art hitherto executed in bronze or marble. He eays the addition of about 5 per cent, 

 of antimony to the lead will give it, not only great hardness, but enhance its capa- 

 bility to run into the most delicate details of the work. 



Baron Wetterstedt's patent sheathing for ships consists of lead, with 2 to 8 per 

 cent, of antimony ; about 3 per cent, is the usual quantity. Tho alloy is rolled out 

 into sheets. We are not aware that this alloy has ever been employed. 



Emery wheels and grinding tools for tho lapidary are formed of an alloy of anti- 

 mony and lead. 



Organ pipes are sometimes made of lead and tin, the latter metal being employed 

 to harden the lead. The pipes, however, of the great organ in the Town Hall a 

 Birmingham are principally made of sheet zinc. 



Lead and arsenic form shot-metal. The usual proportions are. said to be 401bs. of 

 metallic arsenic to one ton of lead. 



In addition to these, the alloys of iron appear of sufficient importance to require 

 some further notice. 



IRON and MANGANESE. Mr. Mushet concludes, from his experiments, that the 

 maximum combinations of manganese and iron is 40 of the former to 100 of the 

 latter. The alloy 71'4 of tin and 28'6 of manganese is indifferent to the magnet. 



IRON and SILVER ; STEEL and SILVER. Various experiments have been made 

 upon alloys of iron and steel with other metals. The only alloys to which sufficient 

 importance has been given are those of iron and silver and steol and silver. M. 

 Guyton states, in the ' Annales de Chimie,' that he found iron to alloy with silver in 

 greater quantity than the silver with the iron. ' Iron can,' he says, ' therefore no 

 longer be said to refuse to mix with silver ; it must, on the contrary, bo acknowledged 

 that those two metals, brought into perfect fusion, contract an actual chemical union ; 

 that, whilst cooling, the heaviest metal separates for tJtc greatest part ; that notwith- 

 standing each of the two metals retains a portion of tho other, as is the case in every 

 liquation, that the part that remains is not simply mixed or interlaid, but chemically 

 united ; lastly, that the alloy in these proportions possesses peculiar properties, 

 particularly a degree of hardness that may render it extremely useful for various 

 purposes.' 



The experiments of Faraday and Stodart on the alloys of iron and steel are of great 

 value ; the most interesting being the alloy with silver. The words of these experi- 

 mentalists are quoted : 



'In making the silver alloys, the proportion first tried was 1 silver to 160 steel; 

 the resulting buttons were uniformly steel and silver in fibres, the silver being like- 

 wise given out in globules during solidifying, and adhering to the surface of the fused 

 button ; some of these, when forged, gave out more globules of silver. In this state 

 of mechanical mixture the little bars, when exposed to a damp atmosphere, evidently 

 produced voltaic action ; and to this we are disposed to attribute the rapid destruction 

 of the metal by oxidation, no such destructive action taking place when the two metals 

 are chemically combined. These results indicated the necessity of diminishing tho 

 quantity of silver, and 1 silver to 200 steel was tried. Here, again, were fibres and 

 globules in abundance ; with 1 to 300 tho fibres diminished, but still were present ; 

 they were detected even when 1 to 400 was used. The successful experiment remains 

 to be named. When 1 of silver to 500 steel were properly fused, a very perfect 

 button was produced ; no silver appeared on its surface ; when forged and dissected 

 by an acid, no fibres were seen, although examined by a high magnifying power. 

 The specimen forged remarkably well, although very hard; it had in every respect the 

 most favourable appearance. By a delicate test every part of the bar gave silver. 

 This alloy is decidedly superior to the very best steel ; and this excellence is un- 

 questionably owing to a combination with a minute quantity of silver. It has been 



