8 TEE POPULAR SCIENCE MONTELY 



called rudimentary even as compared with the earlier chemical phi- 

 losophy 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 mathe- 

 matics, astronomy and certain fields of physics, had brought to chem- 

 istry 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 Eenaissance was a medley of 

 Greek Galenism, oriental mysticism and medieval superstition, so the 

 chemical philosophy of the time was a medley of Aristotelian phi- 

 losophy, 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 ac- 

 cepted 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 essen- 

 tial 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 



