1. _Mercury with bismuth and lead._ When the amalgam formed of 2 atoms bismuth and 1 of mercury is mixed with that formed by 1 atom of lead and 1 of mercury, in such proportion that the mercury is the same in both, the two powders, though dry and crystalline at first, soon become a permanently fluid amalgam by trituration. The liquid in running along _drags a tail after it_, and is disposed to separate into portions less and more fluid, but the most fluid part is much inferior to pure mercury in this respect. Specific gravity of the amalgam, 11. 2. _Mercury with fusible metal composed of 7 bismuth, 5 lead and 3 tin._ A mixture of 4 parts fusible metal with 5 parts mercury compose the most fusible amalgam with a minimum of mercury that I have found. It is formed of 2 atoms bismuth, 1 lead, 1 tin and 2 mercury. Its specific gravity is 12. 3. _Mercury, zinc and tin._ This amalgam is found the most effectual for the excitation of electric machines. Mr. Cuthbertson recommends 1 part zinc, 1 tin and 2 of mercury for the plate machine amalgam. But for a cylinder the best amalgam I have made contains more than twice the above portion of mercury. I form an alloy of 58 parts zinc and 52 tin, (2 atoms to 1). To this alloy I add 250 mercury, and fuse the mixture; the liquid mass crystallizes about 222° into a white, moderately hard amalgam. This is pulverized in a mortar and mixed up with ¹/₁₂ of its weight of hog’s lard. A small portion then is spread upon a piece of leather and applied to the machine when in action. It is probable however that a harder and less unctuous amalgam may be better adapted to the plate machine. This amalgam of mine consists of 4 atoms of zinc, 2 of tin and 3 of mercury. I have tried the amalgams of zinc and tin separately and find that they answer for electric excitation as well as when combined. They ought to be formed of 2 atoms zinc and 1 of mercury (58 parts to 167), and of 2 atoms tin and 1 of mercury (104 parts to 167). If we choose to combine them, we have only to take 2 parts of the zinc amalgam and 1 of the tin amalgam and triturate them together. Bismuth amalgam is not good for electric excitation; lead amalgam is better; but they are much inferior to those of tin and zinc. _Alloys of Copper with other Metals._ 1. _Copper and iron._ These two metals may be united with difficulty by heat; but the compound possesses no useful property. 2. _Copper and nickel._ A white, hard, brittle alloy is said to be formed by combining these two metals. The alloy is scarcely known. 3. _Copper and tin._ The metals of copper and tin, may be fused together and united in almost any proportion by skilful treatment; but it is found that only a few of the proportions constitute alloys possessing properties eminently valuable to the arts.