CHEMISTRY. 245 



one example may be cited where a large fortune has followed upon an 

 invention of this kind. 



The origin of the word, as applied to metallic compounds, is no doubt 

 coeval with the age of the so-called "noble" and "base" metals; a form of 

 language naturally leading to the conclusion, that when any noble metal was 

 mixed with a base one, its nobility was "allayed" or "alloyed," and conse- 

 quently diminished. In this sense, the base metal came to be regarded as the 

 allay or alloy, and as such is thus described by an old writer: "Alloy is the 

 proportion of a baser metal mixed with a finer or purer ; as the quantity of 

 copper that is mingled with gold to make it of a due hardness is called the 

 alloy ;" and with tin's meaning the word is still used by our assay ers of gold 

 and silver. But it is clear, from the very nature of the example here chosen, 

 that no admixture of one base metal with another like itself, could generate 

 an alloy in the opinion of writers of the old school ; nor can we anywhere 

 find that brass, bell-metal, &c., were called alloys, until mixed with gold or 

 silver. 



If, however, we now proceed to examine the meaning of the expression 

 alloy, in the present day, we shall find that it extends to every admixture 

 of two or more metals, and is, perhaps, no less absurdly diffuse than it was 

 previously limited. On the new system, 99 parts of gold and one of copper is an 

 alloy of gold ; whilst 99 of copper and one of gold is an alloy of copper : nor 

 is there any fixed or recognised limit at which an admixture of metals ceases 

 to bear the name alloy : in fact, almost every metal we now use might, from 

 its casual impurity, come within the boundaries of this definition. Lead, 

 with a trace of silver, will thus be an alloy of lead ; and iron containing a 

 trace of manganese an alloy of iron. Such a state of things cannot fail in the 

 end to produce uncertainty and confusion ; wherefore we propose to establish, 

 for present purposes at least, a distinction betwixt what we shall call an 

 alloy of metals and an admixture. 



!Many years ago Dr. Dalton drew attention to the fact, that many of the 

 alloys in ordinary use, as brass, &c., were very nearly atomic compounds, or, 

 in other words, mixtures of metals in such proportions, that one combining 

 equivalent of the one was united w r ith one, two, or three equivalents of the 

 other ; and this peculiarity was found to extend to what may be termed 

 native or natural alloys. Thus, brass of good quality consists of about 34 

 zinc and 66 copper in 100 parts, which is very nearly in the proportion of 

 one atom of zinc to two atoms of copper ; and again, the native of alloy of 

 gold and silver, called "electrum," is said by Boussingault to consist of two 

 atoms of gold and one of silver. In fact, many such examples might be 

 pointed out in support of Dalton's opinion, though it is quite certain that in 

 this, as in many other of his assertions, he carried his views too far, and was 

 misled by his mathematical bias. Silver and iron, for example, refuse to unite 

 permanently, and separate on cooling ; but the iron retains, in this case, a 

 small and variable quantity of silver, whilst the silver retains a little iron : 

 similarly lead and zinc comport themselves ; and in neither instance can any 

 reasonable grounds be found for inferring that an atomic combination has 

 ensued. It would appear, therefore, that the union of some metals in atomic 



