delivered the opinion of the court.

The plaintiffs contend that white lead,.nitrate of lead, oxide of zinc, and dry and orange mineral, are “manufactures of metals.” Whether they are or not is the question at issue.

' Unless some special usage to the contrary can be shown, the construction relied on by the plaintiffs is clearly wrong.

When the act speaks of “ manufactures of metals,” it obviously refers to manufactured articles in which metals form a component part. When we speak of manufactures of wood, of leather, or of iron, we refer to articles that have those substances respectively for their component parts, and not to articles in which they have lost their forro entirely, and have become the chemical ingredients of new forms. The qualification which is added to the phrase “ manufactures of metals ” — namely, “manufactures of metals of which either of them” (that1 is, either of the metals) “ is the component part of chief value ” t— corroborates this view.

If the plaintiffs could show a different legislative usage, there would be some plausibility in their position. But this they have failed to do. So far as our attention has been called to the usage, it corroborates the view above expressed. For example: in the act of March 2, 1861, to provide for the payment of outstanding treasury-notes, &c., the import-duties to be levied on lead, copper, and zinc, in various forms, are imposed by the eighth section; whilst those on white lead, oxide of zinc, red lead, litharge, &c., are separately provided for in the ninth section. And in the act passed July 14,1862, for increasing duties, &c., the duties on iron in different forms, and on “ all manufactures of iron,” are provided for in sect. 3, and those on copper and “ manufactures of copper,” and on zinc and lead, in sect. 4; whilst those “ on copperas, green vitriol, or sulphate of iron,” “ on white and red lead,” and “ oxide of zinc,” are provided for in sect. 7; and those on “litharge”' and “verdigris,” in sect. 5. In none of these cases is there an intimation that the classes of articles named lap on to each other, or that one duty imposed is exceptional to another; and yet, if the position óf the plaintiffs is correct, copperas is a manufacture of iron, white, and red led and litharge are manufactures of lead, and verdigris is a manufacture of copper, ■

*577The truth is, that, in the nature of things, a metal and its oxide or sulphate are totally distinct and unlike. Any substance subjected to a chemical change by uniting with another substance loses its identity: it becomes a different-mineral species. The basis of common clay is the metal aluminium, and the basis of lime is the metal (nlcium. But no one would think of calling clay and lime metals; nor, if artificially made, would he call them manufactures of metals. They have lost all their metallic qualities. In just the same manner, iron ceases to be iron when it becomes rust, which is oxide of iron; or when it becomes copperas, which is sulphate of iron. None would think of calling blue vitriol copper. So white lead, nitrate of lead, oxide of zinc, and dry or orange mineral, are not metals: they have no metallic qualities. In the poverty of language, they have no distinct names, it is true, as lime and clay and' vitriol have; but each is designated by a scientific periphrasis, in which the name of the metal which forms one of its chemical - elements is used. This use of the name has probably been one cause of the confusion which has arisen on the subject.

Judgment affirmed.