SCIENCE. 



[N. S. Vol. XI. No. 277. 



structural formula involves an extension of 

 the older atomic hypothesis, in that it as- 

 serts definitely that the combining atoms 

 do not blend, but come into juxtaposition 

 in some orderly and systematic fashion, 

 while stereochemistry, or chemistry in 

 space, asserts that the parts of these sys- 

 tems are to a certain extent fixed in relative 

 position, not rotating about each other after 

 the manner of the members of the solar 

 system. As to the inner nature of the atom 

 itself, however, it says absolutely nothing. 



To sum up, the laws of Constant and 

 Multiple Proportions have led the chemist 

 to regard matter as not continuous, but com- 

 posed of units or atoms, these having the 

 same mass and specific chemical properties 

 in the same element, but other masses and 

 other chemical properties in other elements. 

 Innumerable facts lead him to believe that 

 the atoms in the molecule are not blended, 

 nor so juxtaposed as to have an arbitrary 

 and constantly varying relation, but com- 

 bined in such a manner that there is a more 

 intimate relation between some atoms than 

 others, some forming connecting links be- 

 tween the rest, a relation which is schemat- 

 ically represented by structural formulas. 

 Finally, stereochemical phenomena indicate 

 that the molecule possesses a certain defi- 

 nite geometrical structure, not necessarily 

 rigid, but not having a mobility of its parts 

 analogous to that of the parts of the solar 

 system. As to the further divisibility of 

 the atoms, their unalterableness, indestruc- 

 tibilitj'^, form, origin, and, in short, their 

 absolute nature, the chemist knows nothing 

 and has no opinion of real weight — for him 

 they are merely centers through which 

 energy manifests itself. 



If those who adopt the atomic theory 

 would carefully distinguish between essen- 

 tials and non-essentials, and if those who 

 deny the possibility of interpreting vital 

 phenomena in terms of physics and chem- 

 istry would bear in mind that we know 



scarcely more of the inner nature of the 

 fragment of carbon than of the protoplasm 

 into whose composition it enters, and that 

 affinity is after all is as great a mystery as 

 consciousness, we might possibly hear less of 

 the impossibility of gross, inert, dead matter 

 containing within itself " the promise and 

 potency of every form and quality of life." 

 H. N. Stokes. 



S03IE OBJECTIONS TO THE ATOMIC 

 THEORY* 



For the purpose of this discussion, all 

 metaphysical conceptions or discussions are 

 ruled out, and it is explicitly confined to 

 that definition of the atom or molecule con- 

 noted by Dalton's famous'hypothesis with 

 such amplifications or modifications as have 

 been brought about by the subsequent ad- 

 vance of physical science. In its inception 

 the hypothesis was not without objectors, 

 and properly so. 



The efforts of Wallaston and others to 

 insist upon the importance of considering 

 ' combining numbers ' or ' reacting masses,' 

 things which one could really know about 

 and determine experimentally, rather than 

 hypothetical atoms, the existence of which 

 in the nature of things was beyond physical 

 proof, was philosophically sound, as far as 

 it went. But the historical vicissitudes of 

 the hypothesis, interesting though they be, 

 can not be considered here, but rather, at- 

 tention must be given to the comparatively 

 recent discussions on this subject as they 

 have appeared in contemporaneous episte- 

 mological writings. 



The attempt will be made to present the 

 present status of the subject with due re- 

 gard to relative perspective values, rather 

 than to cite article and authority in an 

 historical retrospect. Dalton's hypothesis 



* Paper read before the joint meeeting of the 

 Chemical and Philosophical Societies of Washington. 

 Time allotted for this contribution to the program, 

 15 minutes. 



