Many speak of brass as a metal apart from copper, yet the brass of commerce, worked up in many forms, is only a composite metal of which copper is the basis. The popularity of pure copper as the material from which household utensils and many constructional objects of use and ornament were made in the past continued unabated until metallurgical chemists discovered how, by using an alloy of zinc, the metal we call brass could be cast, rolled, and otherwise manipulated. Among the advantages claimed for brass is that it has a harder surface and is more resisting than copper. From the days of Queen Elizabeth onward it was much favoured for domestic vessels, and even at the present time it is used to some extent; there has, however, always been a concurrent use of copper. Bell Metal and Other Alloys. There is yet another important alloy, which from its chief use takes the name of bell-metal; its companion alloy is gun-metal. In the mixing of these metals special alloys are aimed at according to the object in view, that is to say, the ingredients vary, but, broadly defined, the copper and its alloy tin used in bell-metal are in the proportion of three to one. The metal was in the past used for those much employed articles of commercial and domestic use, mortars, in addition to the founding of bells. Bell-metal was also the material of which weights and measures (especially the standards kept in many of the old cities) were chiefly made (see illustrations and references thereto in Chapters X and XI). The Sources from which Copper is Derived. Copper seems to have been very widely distributed all over the world, a fact that has contributed to its general use. At one time a local metal employed in a pure state and in conjunction with alloys, chiefly where it was mined, it is now brought to the metal-founder from other parts of the world. Although vast quantities of copper are now imported into England, it was from British mines that the supply was drawn in days gone by. The Britons understood its use, no doubt finding it out by accident, just as the natives of many other countries have done. Copper, as evidenced by the marvellous Benin bronzes, was known in Central Africa long ago. The mines at Mansfield, in Germany, are the oldest in Europe, and there workers have been digging up copper for seven centuries. The collector of old metal objects naturally takes the greater interest in well authenticated specimens known to have been fashioned in districts once famous for their copper mines. Unfortunately, the Cornish mines produce little ore now. When the Romans worked them they obtained copper quite near to the surface; but such easily mined ores have long been cleared.