464 Frederick Guthrie on Eutexia. 



temperature to the very last, and is the eutectic alloy of these 

 metals. It showed on analysis : — 



Melting 

 Per cent, temperature. 



I : : : : "III} «*• 



Of course this eutectic alloy is now to be made by melting 

 the metals together in the above ratio ; but on account of the 

 oxidation of the zinc at about its melting-point, it is better 

 to provide a little excess of that metal and to remove the 

 excess by the above method. 



§ 198. Bismuth and Tin. — In forming the eutectic alloy 

 of these, the bismuth need be only just fused. A roll of tin 

 foil is stirred into the bismuth, and in spite of the cooling 

 effect, the alloy which is formed remains liquid. When the 

 temperature reaches about 150°, the roll of tin is withdrawn, 

 and the temperature is watched as the alloy cools. The 

 temperature ceases to fall at 133°, which is the fusion tem- 

 perature of this eutectic alloy. Having satisfied oneself of 

 this, the whole may be remelted, and about a quarter having 

 been allowed to solidify at 133°, the rest is poured off, and is 

 pure. This alloy is very finely crystalline when quickly cooled ; 

 it is very brittle and its freshly broken surface closely re- 

 sembles that of cast iron. It showed on analysis : — 



Temperature 

 Per cent, of fusion. 

 Bismuth .... 46*1 ) -. ooo 

 Tin 53-9 J l66 ' 



§ 199. Bismuth and Lead. — Proceeding in a very similar 

 manner as with tin, a fixed temperature of 122°* 7 is reached. 

 This eutectic alloy has the composition : — 



Temperature 

 Per cent. of fusion. 

 Bismuth .... 55 58 1 199 o 7 

 Lead 44'42 J 1ZZ '' 



It is of a bluish grey, is malleable and easily cut or sawn. 



§ 200. Bismuth and Cadmium. — On adding melted cad- 

 mium to melted bismuth and proceeding as above, it is possible 

 to obtain an alloy whose melting-point is 144° C. It shows, 

 on analysis, the following composition : — 



Temperature 

 Per cent, of fusion. 



Bismuth 59-19) 1JJO 



144°. 



Cadmium 40*81 



i 



