56 PHILOSOPHICAL TRANSACTIONS. [ANNO 179& 



8. The next conclusion is founded on the experiments of the allays of copper 

 with steel. It appears that copper may be united to steel without the intermede of 

 any other metal ; for a perfectly homogeneous compound was produced by melting 

 10 parts of copper with 1 of steel, § 6, exper. 19. As this allay was not harder 

 than that of copper with -^th of its weight of tin, and as it did not appear that a 

 compact and uniform malleable metal could be composed of 2 parts of steel with 2 

 parts of copper, fy 6, exper 20, I thought it unnecessary, to make any more experi- 

 ments with different proportions of copper and steel. For, 1st, granting that the 

 allays of copper by steel are as hard, strong, and malleable as those of copper by 

 tin, it is utterly improbable that the ancients should have used steel to harden cop- 

 per; on account of the great scarcity and high price of steel comparatively with tin; 

 and also on account of the difficulty of uniting copper with steel, and the facility of 

 uniting copper with tin. 



2dly. It appears that no allays of copper by steel can be made, which possess the 

 hardness, strength, and malleability required ; but which required properties we 

 obtain by combinations of copper with tin, and with which most indubitably the 

 ancients were well acquainted. Count Caylus has indeed told us, that the ancients 

 had 2 methods of hardening copper ; namely, by cementation, and by allaying it 

 with iron. The first method he has not explained; nor is any method known of 

 hardening copper without addition, except by hammering it; which it is well under- 

 stood cannot produce the required hardness. As to the other method by allaying 

 with iron, I think myself warranted in refusing the Count's single vague evidence; 

 and in admitting the evidence of other plainly decisive experiments ; which consist 

 also with reasoning and analogy. 



Philological, and antiquarian writers, in giving an account of the copper arms 

 and utensils of the ancients, (as they found them much harder than copper, and 

 that they were used for purposes to which copper would have been quite unfit ; and 

 as they saw that the ancients commonly used copper on most of those occasions in 

 which we now use iron or steel) ; were led to imagine, that in ancient times there 

 was an art understood of tempering copper, which had been subsequently lost.* If, 

 instead of feigning such an hypothesis, these writers had examined by analysis the 

 ancient implements which fell under their observation, I cannot doubt that they 

 would have unravelled the mystery. Count Caylus himself had a glorious oppor- 

 tunity of ascertaining the composition of ancient copper instruments, when the 7 

 swords and hollow wheel were found at Genzac in 1751. If he had made but 2 

 adequate experiments, one to detect iron, and the other to detect tin, he would 



* u It appears, says Dr. lorl," in his paper on celts, " that the ancients had an art of tempering and 

 hardening brass to a greater degree than is done at present, or perhaps than is necessary to be done." — 

 Archacol. vol 5, p. 187. With reluctance I must observe, that such an experienced inquirer as Dr. 

 Priestley falls into the error of antiquaries, in asserting, that the ancients had a method, with which we 

 axe not well acquainted, of giving copper a considerable degree of hardness, so that a sword might be 

 made of it with a pretty good edge. But Pauw tells us, that the Americans were in possession of the 

 secret of giving a temper to copper equal to steel. — Orig. 



