Messrs. F. C. Calvert and R. Johnson on Alloys. 241 



we must come to the conclusion that all information which may 

 throw light on their composition and properties must enhance 

 their value and applications. 



Alloys have been made, up to the present time, according to 

 habit ; and the proportions used to compose them have been the 

 results of arbitrai-y judgements, instead of fixed and determined 

 chemical proportions. It seemed to us probable, that as all the 

 compounds of chemistry result from the combination of their 

 elements in definite proportions, the same must occur with 

 metals operated upon under circumstances which would allow 

 them to combine freely. If, in ordinary circumstances, definite 

 compounds are not formed, it is owing to the presence of an ex- 

 cess of one or more of the metals which enter into the composition 

 of the alloys, and to the real definite compound being solidified in 

 the mass of the metal in excess ; just in the same way as when 

 bismuth or sulphur are melted in a crucible and allowed to cool, 

 as we all know, the well-defined crystals of bismuth or sulphur 

 are immersed in the excess of bismuth or sulphur which has not 

 been able to crystallize. 



AVe were therefore inclined to believe, that by producing 

 alloys having a definite composition, we should point the way to 

 much cheaper and better alloys than hitherto ; for there can be 

 no doubt that the irregularity of the quality of the alloys of 

 commerce is owing, not only to an excess of one of the metals, 

 but also to a portion of this excess combining with a definite 

 alloy and modifying the composition ; thus, if it is a very fusible 

 metal which is in excess, it will remain liquid and combine with 

 the last portion of the real alloys, and form one which will have 

 a difi"erent composition from that which was formed at first on 

 the outside of the mass ; whilst, on the contrary, if it is a less 

 fusible metal which is used in excess, it will solidify before the 

 predominant alloy of the mass of the casting and prevent its 

 homogeneity. It is to avoid this serious evil that bronze can- 

 nons are cooled at the present day shortly after being cast, so 

 as to keep the mass as uniform as possible ; and the result has 

 been, that instead of having, as formerly, one-third of the bronze 

 pieces of ordnance defective, now only about one-tenth are so. 



Before entering into the details of our researches, it is our 

 duty to state, that during our experiments, Messrs. Levol, Rieffel, 

 and Joule have published papers on some alloys and amalgams 

 having definite proportions. 



The alloys of gold and silver, of gold and copper, and of silver 

 and lead, analysed by M. Levol, are very interesting, and many 

 of them, we have no doubt, are definite compounds, as their 

 respective equivalent proportions are low ; but as to those ana- 

 lysed by M. Rieffel, we have doubts ag to their definite compo- 



