lines, the which though they be not bent and rebounded, but stretched between the thing that is seen and the sight: yet they pass not always forthright, but other whiles they blench some whether, aside from the straight way. And that is when divers manners spaces of divers clearness and thickness be put between the sight and the thing that is seen. Aristotle rehearseth these five mean colours [between white and black] by name, and calleth the first yellow, and the second citrine, and the third red, the fourth purple, and the fifth green. In the book Meteorics, a little before the end, Aristotle saith that gold, as other metals, hath other matter of subtle brimstone and red, and of quicksilver subtle and white. In the composition thereof is more sadness of brimstone than of air and moisture of quicksilver, and therefore gold is more sad and heavy than silver. In composition of silver is more commonly quicksilver than white brimstone. Then among metals nothing is more sad in substance, or more better compact than gold. And therefore though it be put in fire, it wasteth not by smoking and vapours, nor lesseth not the weight, and so it is not wasted in fire, but if it be melted with strong heat, then if any filth be therein, it is cleansed thereof. And that maketh the gold more pure and shining. No metal stretcheth more with hammer work than gold, for it stretcheth so, that between the anvil and the hammer without breaking and rending in pieces it stretcheth to gold foil. And among metals there is none fairer in sight than gold, and therefore among painters gold is chief and fairest in sight, and so it embellisheth colour and shape, and colour of other metals. Also among metals is nothing so effectual in virtue as gold. Plato describeth the virtue thereof and saith that it is more temperate and pure than other metals. For it hath virtue to comfort and for to cleanse superfluities gathered in bodies. And therefore it helpeth against leprosy and meselry. The filings of gold taken in meat or in drink or in medicine, preserve and let breeding of leperhood, or namely hideth it and maketh it unknown. Orpiment is a vein of the earth, or a manner of free stone that cleaveth and breaketh, and it is like to gold in colour: and this is called Arsenic by another name, and is double, red and citron. It hath kind of brimstone, of burning and drying. And if it be laid to brass, it maketh the brass white, and burneth and wasteth all bodies of metal, out take gold. Though silver be white yet it maketh black lines and strakes in the body that is scored therewith. In composition thereof is quicksilver and white brimstone, and therefore it is not so heavy as gold. There are two manner of silvers, simple and compound. The simple is fleeting, and is called quicksilver; the silver compounded is massy and sad, and is compounded of quicksilver pure and clean, and of white brimstone, not burning, as Aristotle saith.