574 SCIENTIFIC THOUGHT. 



up again in the course of the century, and is at present 

 occupying the attention of distinguished thinkers. It 

 will be interesting to give some account of these prac- 

 tical applications. 

 IB. Of these, four notably attract our attention. First, 



Four ap- 

 plications, the theory of error, prominently associated ^ with the 



name of Gauss. Secondly, the writings of Adolphe 

 Quetelet, and the great impetus given by him to 

 statistical research. Thirdly, the peculiar development 

 of the Atomic theory known as the Kinetic theory 

 of gases, which gave to many scientific investigations 

 what Clerk - Maxwell termed the statistical, in oppo- 

 sition to the historical or descriptive, character. Lastly, 

 the Darwinian ideas which deal with the great and 

 increasing numbers of living things, and the changes 

 inherent in their growth and development. These 

 have led to statistical enumerations and registrations 

 which, beginning with Mr Francis Galton's researches 

 into the phenomena of heredity, are at the present 

 moment being continued on special lines by Prof. Karl 

 Pearson. 

 17. That Error is subject to law, or, to express it mathe- 



Theory of 



Error. matically, to regularity, is a reflection which forced itself 

 upon the attention of thinkers who occupied themselves 

 with the doctrine of chances, and of statisticians who 

 collected registers of large numbers of events. Let 

 special known sources of error be eliminated or allowed 

 for in every instance, there still remains a very large, 

 practically an infinite, number of unknown sources of 

 error which where we have to do with simple magni- 

 tude may increase or reduce our result by mutually 



