870 Transactions of the American Institute. 



matter in which it exists in successive degrees of increasing density ; 

 and that these conditions form the connecting links, so to speak, 

 between its apparently imponderable and its ponderable states. 

 Something like this opinion seems to have been maintained in a curi- 

 ous work published, in England, many years ago.* The reverend 

 author, viewing the universe as a systematic manifestation of the 

 Divine "Will, assumes that the medium of light is the mother element 

 from which, by progressive steps, the chemical elements have been 

 evolved. Proceeding from the first lines of morphology, he arrives- 

 at the primitive form which cannot be isolated ; then, by an exceed- 

 ingly ingenious synthetic process, he represents by diagrams his ideal 

 structure of different kinds of atoms, all of which are duplications of 

 the tetrahedron. Thus he claims to reveal the unit, by multiples of 

 which the atomic weight of all chemical elements may be expressed, 

 and so arrives at a result which will be recognized as simply a modifi- 

 cation of the so-called law of Prout. This, and other remarkable 

 surmises by Macvicar are, for reasons which need not here be adduced, 

 quite untenable, nevertheless, he seems to have led the way to an 

 assumption which has recently met with some favor, namely, that the 

 chemical atom, although indivisible, is a collection of smaller particles. 

 However, in following this author toward the infinitesimal, we only 

 realize more fully the truth that above and below the narrow zone of 

 the visible are objects too far off and too fine for human scrutiny. 

 Although the seeming all is rounded by intimations of other and 

 brighter regions, science can never compass them by any extension of 

 her domain ! In those unsounded depths which form the boundary 

 and background of the known, thought, grown dizzy, finds no sup- 

 port ; and even the positivist turns back, bewildered, when mensura- 

 tion fails, and computations end in surds ! 



On examining the numerous works on chemistry published within 

 the last twenty years, one cannot fail to notice a gradual change in 

 the expressions employed in describing reactions. The word " equiva- 

 lent " seems to have lost the meaning originally assigned to it by 

 Wollaston, and the terms "combining weight" and " combining pro- 

 portion " are now used less frequently than " atomic weight " and 

 "atom." This abandonment of old forms of expression, doubtless, 

 indicates a gradual change of opinion among leading chemists, a 

 change which may . be ascribed partly to an accumulation of facts 

 tending to confirm the atomic theory, and partly to the promptings 



* Elements of the Economy of Nature. By J. G. Macvicar, D. D. London : 

 Chapman and Hall. 1856. 



