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THE POPULAR SCIENCE MONTHLY 



mists who, with the possible exception of an occasional Paracelsus, 

 sought hap-hazard for the transmutation of the metals, has been vindi- 

 cated by the disintegration theory of atoms and the discussion of the 

 possible transmutation of one chemical element into another. This is 

 doing altogether too much honor to the alchemists whose only object was 

 personal enrichment; there is no credit due to them; the most extrava- 

 gant theory may be realized under suitable conditions and in this mys- 

 terious universe any condition or concurrence of conditions seems to be 

 possible. 



Theories of Matter 



Eor the belief that all matter may have a common origin, we must 

 go back twenty-five centuries to Thales of Miletus and the hylozoistic 

 school; it is another case of the premature leakage of subliminal wis- 

 dom. Sir Norman Lockyer can be said to have put the theory into 

 tangible form by his work on stellar evolution which has developed the 

 fact that the complexity of stellar matter is a function of its tempera- 

 ture. The higher the temperature of a star is, the fewer and the 

 simpler are the elements present. Wiirtz wrote that "the diversity of 

 matter results from primordial differences, perpetually existing in the 

 very essence of these atoms and in the qualities which are the manifes- 

 tation of them." Ascribing a common origin to all matter would tend 

 to make the formation of new compounds from heterogeneous chemical 

 elements appear more rational. 



The problem of the ultimate structure of matter has stirred the 

 philosophers of all ages, Democritus and Leucippus were the real dis- 

 coverers of the atomic theory, and Lucretius was its poet ; but the times 

 were not propitious for its use as a working hypothesis; it was not, 

 therefore, until revived by Gassendi and adopted by Dalton, that it 

 became acceptable to science. As long as the chemist was obliged to 

 work with molar masses of matter, his work was unsystematic and in a 

 great measure fruitless ; the atomic theory put things in their place and 

 gave the chemist definite molecular masses with which to work. The 

 proof of the atom has been its results; we have not here a question of 

 nature, nor a question of form to discuss ; the atom is a fad in chem- 

 istry, even if it has no existence in any conceivable form. Molar masses 

 are continuous aggregates of molecules; molecules are definite aggre- 

 gates of atoms. The selective qualities of atoms, the phase-rule, etc., 

 belong at present more to chemistry than to physics, and they will, there- 

 fore, be left out of the discussion. Molar activity is known by its com- 

 paratively slow mechanical effects; atomic and molecular activity are 

 known as heat and other forces, and as we go down the scale of size we 

 find the activity more intense. But if it is unnecessary for the purpose 

 of this exposition to discuss atoms and atomic aggregates, it is very im- 

 portant to understand the role of ions. 



