Page:Popular Science Monthly Volume 53.djvu/555

Rh form. The long history of its successive advances and its systematic tentatives, in both the practical and the philosophical departments, is most remarkable.

In the period that followed the Alexandrine epoch and preceded the definite recognition and naturalization of alchemy in western Europe, in the thirteenth century, the name of the Arabians is predominant; and the most widely known authors usually ascribe to them the progress which the Greeks made in most of the sciences. They have sometimes even gone so far as to attribute to the Arabs the discovery of chemistry—a view which has to be abandoned on obtaining an exact knowledge of the original authors.

I have devoted nearly ten years to the study of this subject, and have published for the first time the texts of the Grecian chemists, as well as those of their Syrian and Arabian followers, drawing them from their hiding places in the libraries of London, Paris, and Leyden—works which no one would read, because they were supposed to be chimerical and unintelligible. Yet there is a real and profound science in these old texts, mingled, it is true, with erroneous notions concerning the transmutation of metals, and with illusionary and often charlatanish pretensions.

Except gold, which has been mined native from the earliest times, pure metals are rarely found in Nature. A native alloy of gold and silver is found in similar conditions as gold, which was called white gold or electrum by the ancients, and was considered a separate metal till the sixth century It was used as a material for money by the Lydians, and by the Grecian cities of Asia Minor, till near the time of Alexander. This alloy, however, has no constant properties, for the relative proportions of its two components are variable. By reason of this diversity it had an important place in the thought and attempts of the alchemists seeking for the transmutation of metals; for we can extract gold or silver from it at will, according to the treatment we give it. Hence the opinion that electrum was susceptible of being changed into one or the other of these two noble metals.

These notions and experiments were confirmed by the metallurgical methods employed in the fabrication of other metals. Iron, copper, lead, tin, and silver do not exist as such in Nature except in unusual minerals. They are ordinarily found in oxide or sulphide compounds, and are, when separate, products formed by human art. In fact, it is by submitting these compounds to more or less complicated reactions, in which fire, combustible agents, drying, or roasting in contact with the air are applied, that the different metals are prepared. These preparations were formerly made according to a traditional empiricism, the origin of which is lost in the