will flow on the surface, and be easily blown off by the bellows: the antimony all evaporates, and leaves the gold alone. This is called the last test of gold, to try the purity of it. If the remaining gold have lost nothing of its weight, it is allowed perfectly pure, and called gold of twenty-four carats; or if it be found 1/24 lighter, it is said to be twenty-three carats fine.
*But as to the ductility of gold, this is the most extraordinary property of it. The arts of gold-beating and wire-drawing, shew us things quite amazing. In leaf-gold, a grain and a quarter of the metal, may be made to cover an area of fifty square inches; and if the leaf be divided by parallel lines 1/100 part of an inch, a grain of gold will be divided into five hundred thousand minute squares, all discernible by the eye: yet this is not the most can be done by the hammer. A single grain of gold may be stretched into a leaf that will cover a house, and yet the leaf remain so compact, as not to transmit the rays of light, nor ever admit spirit of wine to transude. This however is nothing to the effects of wire-drawing.
A gold wire is only a silver one gilt, and if you coat a silver cylinder of forty-eight ounces weight, with one ounce of gold, which is sufficient, this cylinder may be drawn out into a wire so very fine, that two yards thereof

shall weigh only one grain, and 98 yards only 49 grains, so that one grain of gold gilds 98 yards; and of course the ten thousandth part of a grain, is above one third part of an inch long. And since the third part of an inch is yet capable of being divided into ten lesser parts visible to the eye, it is evident that the hundred thousandth part of a grain of gold, may be seen without the help of a microscope: And yet so intimately do its parts cohere, that though the gold wherewith the wire is coated, be stretched to such a degree, there is not any appearance of the colour of silver underneath. Nor is this all.
In supergildings, that is, to make the richest lace, they employ but 6 ounces of gold, to cover or gild 45 marks of silver, that is, twenty-two pounds and a half avordupoise weight, rounded into the form of a cylinder or roller, which hath fifteen lines in diameter, and twenty-two inches in