48 PHILOSOPHICAL TRANSACTIONS. [ANNO 179^5. 



(a) The blue solution of this experiment being boiled, to carry off redundant 

 acid, and evaporate about 4-ths of its water, prussiate of soda was added. A red- 

 dish-brown precipitation ensued, which resembled exactly that produced by adding 

 this test to nitrate of copper. 



(b) The white deposit of this experiment having been well edulcorated by pure 

 water was wholly dissolved in muriatic acid. This solution differed from that of all 

 the white deposits of the preceding experiments, in being of a reddish-brown co- 

 lour, like dilute solution of muriate of iron, and especially in affording a copious 

 precipitation of prussiate of iron by prussiate of soda. With nitro-muriate of gold 

 however, this solution only produced a slight grey precipitation, as in the former 

 experiments. 



Exper. 18. 1000 grs. of the allay of experiment 15 were melted with 2000 grs. 

 of copper. This allay of about 7 parts of copper with 2 parts of tin, and 1 part 

 of steel, was an extremely hard metal, much harder than that of the last experi- 

 ment ; and it was very strong, but scarcely malleable. It took a beautiful polish, 

 of a silvery colour. It was of a perfectly homogeneous texture. The grain of its 

 fracture was extremely fine and uniform, and of a grey colour. 



Exper. 19. 2000 grs. of copper were melted with 200 grs. of steel, in a close 

 vessel, by keeping them exposed to a fierce fire in a wind-furnace for about 20 mi- 

 nutes. This allay of 10 parts of copper with 1 part of steel, was of a copper co- 

 lour. The grain of its fracture was coarse, like that of copper. It was harder 

 than copper, and less tough, but quite malleable. It was about as hard as the allay 

 of 20 parts of copper by 1 of tin, and consequently was not nearly so hard as the 

 softest of the ancient metals. 



Exper. 20. 1000 grs. of copper with 500 grs. of a small round steel file were 

 exposed to fire, as stated in the last experiment. On opening the crucible, part of 

 the steel only was found to have been melted and united to the copper ; but the 

 other part of the steel which retained its form, was thoroughly impregnated or pe- 

 netrated by copper ; so that on breaking the part which had not been melted, and 

 which was very brittle and porous, it was in appearance imperfectly metallized cop- 

 per. The part of the allay which had been melted was not different from the allay 

 of the last experiment, except that it was a little harder ; being thought to be about 

 as hard as brass. 



Then follows a statement of the specific gravities of the different allays above de- 

 scribed, which run variously between the limits 7.2 and 9. 



^ 7- Conclusions and remarks. — 1. The first conclusion, from the preceding ob- 

 servations and experiments is, that the ancient metal instruments examined consist 

 principally of copper, as appears ; 1st, from their external and obvious properties ; 

 particularly their colour, taste, malleability, and specific gravity : 2dly, from the 

 whole of the metals, except a small deposit, yielding nitrate of copper with nitric 

 acid : 3dly, from the synthetic experiments. 



2. 1 conclude that these metal instruments contain tin ; which metal was made 



