Element Cobalt, Co, Transition Metal. Have been known for millennia. Glass ingots have been recovered from Egyptian ancientries such as jar dating to the 15. , in coloring of which cobalt salts. Had been used, as well as in the cobalt. Ancient Assyrians and Babylonians used to produce blue paints which were used for ceramics glazing. Contained sapphire was the initial material from which the names of blue paints came.

Element Copper, Cu, Transition Metal. Between the metals of the new group, which is called after copper. Of the heavy metals already discussed, copper. Besides being used in the pure state, copper. Is also extensively employed for alloys. Brass has already been mentioned; others will be given later. Of the Sinai Peninsula were extensively worked by the Egyptians about the year 3700 b. Must have been known in Cyprus for many centuries previous to their production. Copper daggers found in Northern Italy .

Element Gold, Au, Transition Metal. May have been the first known metal used for ornamentation since Neolithic age, 5000 - 4000 years BC. In Egypt, Mesopotamia, India, China and other ancient countries golden ornamentation. Had been used since 3-2 millennia BC. Alchemists called it the king of metals. Is a trace element; its abundance is 4.

Element Iridium, Ir, Transition Metal. Syssertskite, platinum, rhodium and ruthenium nevyanskite and aurosmirid. They contain also several other mineral forming elements and belong to the solid solutions class.

Element Nickel, Ni, Transition Metal. Unlike cobalt, which is not employed in the metallic state, metallic nickel is a material which is greatly used. It was formerly used only for alloys; thus German silver is an alloy of nickel with zinc and copper. Some decades ago, however, the difficulties caused by the high temperature of fusion of nickel. The electrical deposition of a metal depends on the fact that at the cathode of a circuit, the cations pass from the state of ions into the neutral state.

Element Rhodium, Rh, Transition Metal. Was discovered in 1803 by William Hyde Wollaston, soon after his discovery of palladium. Wollaston dissolved raw platinum in aqua regia. The acid surplus was neutralized by caustic soda. He then precipitated the platinum by adding ammonium chloride, NH. Cl; palladium was removed as palladium cyanide after treating the solution with mercuric cyanide.

On account of its remarkable properties and of its occurrence in the metallic state, silver. In the pure state silver is a white tenacious metal, which can be readily drawn into wire, and made into very thin sheets by rolling or hammering. For use it is alloyed with 10 per cent of copper in order to make it harder. It conducts heat and electricity very well, and occupies, in this respect, the first place among the metals. Is also found in native form.