If, on the contrary, to one part of Tin ten parts of Copper be added, together with a little Zink, a semi-metal to be considered hereafter, from this combination there results a metalline compound which is hard, brittle, and very sonorous; so that it is used for casting bells: this composition is called _Bronze_ and _Bell-metal_. Tin hath an affinity with the vitriolic, nitrous, and marine acids. All of them attack and corrode it; yet none of them is able to dissolve it without great difficulty: so that if a clear solution thereof be desired, particular methods must be employed for that purpose; for the acids do but in a manner calcine it, and convert it to a kind of white calx or precipitate. The solvent which has the greatest power over it is _aqua regis_, which has even a greater affinity therewith than with Gold itself; whence it follows, that Gold dissolved in _aqua regis_ may be precipitated by means of Tin; but then the _aqua regis_ must be weakened. Gold thus precipitated by Tin is of a most beautiful colour, and is used for a red in enameling and painting on porcelain, as also to give a red colour to artificial gems. If the _aqua regis_ be not lowered, the precipitate will not have the purple colour. Tin hath the property of giving a great lustre to all red colours in general; on which account it is used by the dyers for striking a beautiful scarlet, and tin vessels are employed in making fine syrup of violets. Water does not act upon this metal, as it does upon Iron and Copper; for which reason it is not subject to rust: nevertheless, when it is exposed to the air, its surface soon loses its polish and splendour. Tin mixed with nitre and exposed to the fire deflagrates with it, makes it detonate, and is immediately converted to a _refractory calx_: for so all substances are called which are incapable of fusion. Tin readily unites with sulphur, and with it becomes a brittle and friable mass. SECTION VI. _Of_ LEAD. Next to Gold and Mercury Lead is the heaviest of all metalline substances, but in hardness is exceeded by every one of them. Of all metals also it melts the easiest except Tin. While it is in fusion there gathers incessantly on its surface, as on that of Tin, a blackish dusty pellicle, which is nothing but a calx of Lead. This calx further calcined by a moderate fire, the flame being reverberated on it, soon grows white. If the calcination be continued it becomes yellow, and at last of a beautiful red. In this state it is called _Minium_, and is used as a pigment. _Minium_ is not easily made, and the operation succeeds well in large manufactures only. To convert Lead into _Litharge_, which is the metal in a manner half vitrified, you need only keep it melted by a pretty strong fire; for then as its surface gradually calcines, it tends more and more to fusion and vitrification.