230 Sir. Mallet on the Physical Conditions 



representing some of the more probable forms of constitutional arrangement of 

 the whole mass, in each of the four preceding alloys, after consolidation. 



No. 1. 100 : 9 =83Cu + 4Sn 



= 4 (Cui; + Sn) + Cu,5 



= 3 (Cu„ + Sn) + (Cus + Sn) + Cu,4 



= 3 (Cu„ + Sn) + 0-5 (Cu48 + Sn) + 0-5 (Cuis + Sn) 



= 2 (Cu34 + Sn) + 2 (Cu7 + Sn) + Cu. 



No. 2. 100 : 10 =56Cu + 3Sn 



= 3(Cun + Sn) + Cu5 



= 2 (Oui7 + Sn) + (Cus + Sn) + Cuu 



= (Cu34 + Sn) + (Cu,7 + Sn) + (Cu^ + Sn) + Cu 



= (Cus, + Sn) + 0-5 (Cus + Sn) + 05 (Cu^ + Sn). 



No. 3. 100:11 =17Cu + Sn. (Normal gun-metal.) 



No. 4. 100 : 12 =31Cu + 2Sn 



= (Cu,7 + Sn) + (Cus + Sn) + Cus 



= (Cuj7 + Sn) + (Cu,2 + Sn) + Cu^ 



= (Cu,7 + Sn) + 0-5 (Cui6 + Sn) + 0-5 (Cu,o + Sn) 



Analyses quoted by Moritz Meyer, of the Russian service, and verified in 

 France by Ravichio de Peretsdorf, proved the segregated alloy in many cases 

 to have the constitution (6 Cu + Sn), an alloy as hard as bell-metal. (See 

 Table x. 6.) 



Applying this to the empiric formula No. 1, we obtain such rational for- 

 mulse as the following : — 



83 Cu -t- 4 Sn 

 = 3 (Cun + Sn) ■\- (Cue -t- Sn) + Cu^e 

 = 2 (Cui7 -h Sn) -f (Cum + Sn) + (Cu,^ + Sn) + Cm, 

 = (Cuss + Sna) -1- (Cui5 + Sn). 



All which agree with the former in this, that the total compound is broken up into 

 two or more alloys, the copper in one of which (normal gun-metal, 17 Cu + Sn) 

 bears to that of any of the segregated alloys, the ratio of 17 : n x 2. These 

 are incommensurable numbers; and hence the primary cause of segregation 

 shows itself to consist, not in separation merely, through difference of specific 



