A HISTORY OF SCIENCE 



coign of vantage, which can never be successfully as- 

 sailed unless by a new host of antagonistic facts. Such 

 generalizations, with the events leading directly up to 

 them, have chiefly occupied our attention. 



But a moment's reflection makes it clear that the 

 battle of science, thus considered, is ever shifting 

 ground and never ended. Thus at any given period 

 there are many unsettled skirmishes under way ; many 

 hypotheses are yet only struggling towards the strong- 

 hold of theory, perhaps never to attain it; in many 

 directions the hosts of antagonistic facts seem so evenly 

 matched that the hazard of war appears uncertain ; or, 

 again, so few facts are available that as yet no attack 

 worthy the name is possible. Such unsettled contro- 

 versies as these have, for the most part, been ignored 

 in our survey of the field. But it would not be fair to 

 conclude our story without adverting to them, at least 

 in brief; for some* of them have to do with the most 

 comprehensive and important questions with which 

 science deals, and the aggregate number of facts in- 

 volved in these unfinished battles is often great, even 

 though as yet the marshalling has not led to final vic- 

 tory for any faction. In some cases, doubtless, the 

 right hypothesis is actually in the field, but its suprem- 

 acy not yet conclusively proved perhaps not to be 

 proved for many years or decades to come. Some of 

 the chief scientific results of the nineteenth century 

 have been but the gaining of supremacy for hypotheses 

 that were mere forlorn hopes, looked on with general 

 contempt, if at all heeded, when the eighteenth century 

 came to a close witness the doctrines of the great age 

 of the earth, of the immateriality of heat, of the un- 



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