ANCIENT Dismay. The history of ancient phi losophy records certain theories of matter, which have had a directing influence on chemical thought during later centuries. The most im portant ideas date from the Fifth Century B.C. Empedoeles (c.490-30 'Lc.), who may have de rived his views from the ancient philosophers of the East. held that air, water, earth, and tire are four elements unrelated to one another and ft.rming the basis of the universe. Aristotle ( B.C. 3S4-22) added a fifth element, onsia a. purely spiritual substance ing the infinity of space. During the Aliddle Ages not a little energy was lost in researches after this 'fifth essence,' which, by confusion of ideas, came to be regarded as a fifth elementary form of matter. To Aristotle the material ele ments were not altogether different from one an other. hut were forms of a primary substance differentiated by properties—as dry. hot, cold—that were not essential 10 its nature. Hence, later, the alchemists' attempts to turn metals into one another, crowned by the belief that such transmutations cannot be effected by any known means. The atomic conception dates from Democ ritus (c.031-370 tt.c.), who held that all bodies are made up of the atoms of one and the same substance, and that the differences exhibited by the various forms of matter are due entirely to differences in the size and shape of their atoms. It is hardly necessary to state that if this mille t eloped idea of Democritus had not furnished a suggestion that led to the building up of a useful chemical doctrine, it would deserve no mention in the history of science. It is thus clear that the ancients did nothing directly toward the building up of a science of chemistry. Indeed, how much chemical knowledge can we expect to find in an age when a man like Aris totle did not hesitate to assert that a vessel will hold as much water if filled with ashes as when empty? However. the ancients knew some facts and processes which lie within the scope of modern chemistry. Most of that knowledge was gained empirically by the Egyptians, and was by them communicated to the Jews and Phoenicians. and later to the Greeks and Romans. The metallurgy of gold, silver. copper, iron. lead, tin, mercury. and perhaps zinc, and the preparation of certain alloys, were known at quite an early date. The Egyptians had highly developed the art of mak ing glass and of coloring it by means of certain nietallie oxides. and many extant specimens, of Egyptian pottery are beautifully enameled in various colors. The art of dyeing fabrics with the aid of mordants had likewise been developed at an early (late, and many mineral and organic coloring matters were known to the Egyptians, Phoenicians, and Jews. The Egyptians were also
probably the first to employ substances for medicinal purposes.
Ar.cilt:Nri. Egypt was the birthplace of al chemy, the pretended art of making gold and silver from base metals. Based on superficial ob servation and the erroneous interpretation of phenomena, this pseudo-art subsequently ab sorbed the attention of men for many centuries (see ALCHEM Y ) . and rendered scientific. progress. and hence the development of the useful arts. impossible. Thus. the arts of metallurgy and of dyeing remained throngh the :Middle Ages prac tically what they had been in Egypt long before the beginning of our era. Nevertheless, in their fantastic search after the philosopher's stone. the alchemists discovered methods of preparing many new substances, perfected many processes of manipulation, and thus slowly paved the way for the future investigator. Bismuth and anti mony. sulphuric, hydrochloric. and nitric acids. the chloride and the carbonate of ammonium. the nitrates of potassium and silver. compounds of mercury. antimony, and arsenic—these and many other important substances were first pre pared and their properties were first studied by the alchemists. Of course, the interpretation of known facts was absurd, based as it. often was on the most groundless assumptions—for in stance, the assumption that most substances and certainly all metals contain sulphur. As to the compounds of carbon, the alchemists did hardly anything toward laying a foundation for future organic chemistry, although they learned to con centrate aqueous acetic acid by distillation and to prepare a few metallic acetates, and were familiar with certain reactions. such as the transformation of ordinary alcohol under the influence of sulphuric acid, the formation of cer tain esters, etc. A number of substances de rived from the organic world were also used for medicinal purposes: but it was not until the beginning of the 'introcheinical' period that the art of preparing substances began to be looked upon as a handmaid of medicine. Alchemy prop er had only one great object in view—to en noble the base metals and to prolong life in definitely—and this remained the principal aim of some of the best men even to the close of the era of iatrochemistry, and even the scientific achievements of more recent times have not suf ficed to banish the fancy completely.