98 



LEAD ALLOYS. Of the alloys of copper and load, Mr. Holtzapffel gives the- following 

 description: Two ounces lead to one pound copper produces a red-coloured and 

 ductile alloy. 



Four ounces lead to 1 pound copper gives an alloy less red and ductile. Neither 

 of these is so much used as those following (p. 100), as the object is to employ as much 

 lead as possible. . 



Tabular Statement of the Physical Peculiarities of ike Principal Alloys, adopted, with 

 tome alterations, from the ' Encyclopedic Tcchnologique.' 



BRITTLE METALS 



AHSENIC 



ANTIMONY 



BISMUTH 



With ZINC, rendering it 



brittle. 



With IKON and STEEL, 

 hardening, whitening, 

 and rendering those me- 

 tals susceptible of a fine 

 polish : much \tsed for 

 steel chains and other 

 ornaments. 



With GOLD, a grey metal, 

 very brittle. 



With COPPER. Composed 

 of 62 parts of copper and 

 32 arsenic, a grey, bril- 

 liant, brittle metal. In- 

 creasing the quantity of 

 copper, the alloy be- 

 comes white and slightly 

 ductile : used in the ma- 

 nufacture of buttons un- 

 der the name of white 

 copper, or TOMBAC. 



With SILVER. 23 of silver 

 and 14 arsenic form a 

 greyish - white brittle 

 metal. 



With LEAD. Arsenic ren- 

 ders lead brittle. The 

 combination is very in- 

 timate ; not decomposed 

 by heat. 



With TIN. Brittle, grey 

 lamollatcd ; less fusible 

 than tin. 



With MERCURY. Without 

 interest. 



This alloy is very brittle. 



30 of iron and 70 of anti- 

 mony are fusible ; very 

 hard, and white. An 

 alloy of two of iron and 

 one of antimony is very 

 hard and brilliant. 



Forms readily a pale yel- 

 low alloy, breaking with 

 a fracture like porcelain. 



Alloys readily : the alloys 

 are brittle. Those formed 

 with equal parts of the 

 two metals are of a fine 

 violet colour. 



These have a strong af- 

 finity; their alloys are 

 always brittle. 



Antimony gives hardness 

 to lead. 24 parts of an- 

 timony and 76 of lead, 

 corresponding to Pb'-'Sb, 

 appear the point of satu- 

 ration of the two metals. 



The alloys of antimony 

 and tin are very white. 

 They become brittle 

 when the arsenic is in 

 large quantity. 



A gritty white alloy. 



Unknown. 



Doubtful. 



Similar to antimony ; of a 

 yellow-green colour. 



Pate-red brittle metnl. 



Alloys brittle and lamol- 

 lated. 



Tile alloys of bismuth and 

 lead are Ipss brittle and 

 more ductile than those 

 with antimony ; but the 

 alloy of 3 parts of lead 

 and 2 of bismuth is 

 harder than load. These 

 alloys are very fusible. 



Tin and bismuth unite in 

 all proportions by fusion. 

 All the alloys are more 

 fusible than tin. 



Mercury dissolves a large 

 quantity of bismuth with- 

 out losing its fluidity ; 

 but drops of the alloy 

 elongate, and form a tail. 



