Page:Popular Science Monthly Volume 87.djvu/12

8 called rudimentary even as compared with the earlier chemical philosophy of Thales, Democritus or Aristotle. The early Greeks had at least reasoned logically from the limited knowledge in their possession. That their generalizations were often more metaphysical than scientific resulted from the fact that their deductions were not based so much on experiment as upon the observation of the more obvious natural phenomena. And, however valuable metaphysical reasoning may be for intellectual discipline, or as a tool in the critical analysis of observed phenomena and their relations, it can not go beyond the facts involved in its premises and can not materially advance the development of experimental sciences. Thus it is safe to say that up to the fourteenth or fifteenth centuries the natural and physical sciences presented few advances and much retrogression from the best days of ancient Greek science.

Arabian scholarship, however it may have contributed to mathematics, astronomy and certain fields of physics, had brought to chemistry little new of value and much of confusion of mysticism and superstition. This statement is largely justified by the results of modern critical investigation which have shown that the works of chemical character attributed to the authorship of Gheber, Avicenna and other Arabian authors are quite generally fabrications of the twelfth to fifteenth centuries, published under those names either to obtain a wider circulation or to avoid the unpleasant consequences that might visit the real authors for dabbling in a suspected or forbidden art. Just as the medical science of the early Renaissance was a medley of Greek Galenism, oriental mysticism and medieval superstition, so the chemical philosophy of the time was a medley of Aristotelian philosophy, with similar infusions of oriental occultism. Many chemical substances were known which to Greeks or Egyptians were unknown—but in so far as any valuable body of theory is concerned, hardly an advance had been made. The chemical theory of the time was mainly of Greek and Egyptian origin filtered, as we have seen, through the Syrian and Arabian sources and for centuries nearly without material progress.

Let me attempt to present the main fundamental concepts of the nature of matter and its changes which constituted the generally accepted chemical theory at the beginning of the sixteenth century, whence we date the revival of chemistry.

The ancient Greeks entertained a very persistent notion of the essential unity of matter. They differed at various times and in different schools of natural philosophy as to the formulation of this theory. Thus some considered that water was the primal element from which all others had been developed, others considered the air as the primal element, others fire. Aristotle finally formulated the notion of the constitution of matter which became the most generally accepted