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The Chinese are said to be extremely expert in the useof the touchstone, so as to distinguish by it so small adifference in the fineness as half a touch, or a two hun-dredth part of the mixt. The touchstone, as I am in-formed, is the only test, by which they regulate the saleof their gold to the European merchants ; and in thosecountries it is subject to fewer difficulties than among us,on account of the uniformity of the alloy, which there isalmost always silver ; the least appearance of copper beingused in the alloy gives a suspicion of fraud. As an assayof the gold is rarely permitted in that commerce, itbehoves the European trader to be well practised in thisway of examination : by carefully attending to the abovedirections, and by accustoming himself to compare thecolours of a good set of touch-needles, it is presumed hewill be able to avoid being imposed on, either in the touch,itself, or by the abuses, said to be sometimes committed,of covering the bar or ingot with a thick coat of finermetal than the interiour part, or of including masses ofbase metal within it. A set of needles may be prepared,,for this use, with silver alloy, in the series of the Chinesetouches > or the needles of the European account may beeasily accommodated to the Chinese, by means of a tableformed for that purpose on the principles already explain-ed. It may be observed, that the gold shoes of China havea depression in the middle, from the shrinking of the metalin its cooling, with a number of circular rings, like thoseon the balls of the fingers, but larger : I have been told,that when any other metallic mass is included within,, thefraud is discoverable at sight, by the middle being elevatedinstead of depressed, and the sides being uneven and knob-by ; but that the same kind of fraud is sometimes practisedin the gold bars, where it is not discoverable by any ex-ternal mark.

III. Of