as they were called, whence our word calamine. The fusion of these minerals with those of copper produced alloys similar to our brass.
While some of these compounds of copper, by virtue of the importance of their applications, thus acquired special names, there were others among the yellow alloys which, employed in antiquity and the middle ages, have fallen into disuse; compounds of copper with arsenic and antimony, for instance, which were useful for promoting the combination of substances like iron with copper or tin, which would not readily unite with them directly. Modern chemistry has very little to do with such alloys. But an alloy of copper and antimony has been revived and patented within the past twenty years which has the appearance and many of the properties of gold. It was known to the Greek alchemists, and is mentioned in the Syriac translations of their works. There existed, therefore, in antiquity and the middle ages, a multitude of artificial metals, passing under the general names of lead, iron, tin, electrum, and gold and silver. Furthermore, as pure silver was confounded in goldsmiths' practice with various alloys designated under the name of asem, so the name of gold was not applied to pure gold alone, but was extended to alloys of that substance with copper and other metals; alloys which differed greatly in richness, but were used for making base goods for which the goldsmiths tried to make their customers pay the price of pure gold. These fraudulent practices and tricks have continued down to our own time in countries where the law has not fixed the standard of merchantable gold and silver with severe penalties for violating it.
With these facts before us we can easily comprehend the ideas and theories of the alchemists, and imagine on what their practices and hopes were based. One of the first ideas their experience gave them was, doubtless, that the properties of the metals varied. The theoretical definition of our simple bodies, which we now know continue unchanged in nature and weight through the course of their metamorphoses, was developed slowly, and was not recognized as a certainty till within a century. The positive minds of the Roman lawgivers no doubt perceived the necessity of employing pure gold and silver, or alloys of a fixed standard, for coinage; but this was a practical prescription, and not a scientific principle. Although the artisans who worked these metals knew how to obtain substances of legal purity, they had no sign to inform them whether these substances really represented a single metal of unchangeable quality, or whether they were dealing with a conventional stage in the undefined series of transformations of matter. These legal divisions applied to gold and silver. There is nothing to prove that any one of the innumerable species of copper, lead, and tin repre-
