170 BULLETIN OF THE 



force really mean ? — Why they are thus and not otherwise ? — Why 

 they are so diverse and irreducible, and each so perfectly auto- 

 cratic ? — Why for example independent molecules bound in the 

 cohesion and adhesion of the " liquid " or the " solid " condition, 

 should exhibit an attraction for each other a thousand-fold stronger 

 than their mutual gravitation ? — Why two atoms within a molecule 

 should cling together with a tenacity only increasing with their en- 

 forced centrifugal separation, while perfectly similar atoms not thus 

 united attract each other with a strength decreasing with the second 

 power of their distance ? — Why the chemical affinity of dissimilar 

 molecules shall attach them with a force incomparably greater than 

 even that of their physical cohesion ? — so that a drop of water may 

 be shattered and lifted by the sun-beam, precipitated in snow, 

 ground beneath a glacier, re-melted and dashed to foam in tumb- 

 ling cataracts, may be combined in the solid substance of a hydrated 

 crystal or in the complex constitution of an organic being, maybe 

 tortured in the chemist's retort or forced in hissing fury through 

 the steam-engine, may pass through protean changes more varied 

 than fable ever fancied, and yet in all these marvellous pilgrimages 

 shall never loosen its structure as a compounded molecule of hydro- 

 gen and oxygen : — Why these same elements — so firmly enchained 

 that the oxygen will quit its grasp only under the decomposing en- 

 ticement of a more powerful affinity, or under the dissociative 

 violence of a molecular velocity and clash representing the temper- 

 ature of highest incandescence, — are yet so averse to separate con- 

 densation that only the combination of extremest cold and pressure 

 attainable by human artifice has succeeded in bringing the molecules 

 of either to a momentary liquid or solid cohesion ? — we find such 

 questionings though irresistibly suggested, as irreversibly removed 

 outside the pale of oracle or answer. There is' no mystery in the 

 world of mind, that is not fully parallelled by mysteries as bewilder- 

 ing in the world of matter. 



Hemmed in by the impassable limitations of a restricted experi- 

 ence and of a no less restricted faculty of reason, we find the finite 

 radius of our science touching in every dh'ection the shadowy uni- 

 verse of nescience ; and where most we seem to know, there most 

 we encounter the cloud-land of the unknowable. In our highest 

 reach and proudest triumph of analytic achievement, — in that 

 symbolical reasoning upon quantitive relation which we call par 

 excellence the " mathematical," — we find that our symbols over-step 



