CHARACTER OF THE EXPERIMENTALISE. 227 



Archimedes, and the ' Principia ' forms the true Novum 

 Orgamim of scientific method. The laws which he 

 actually established are great, but his example of the 

 manner of establishing them is greater still. There is 

 hardly a progressive branch of physical and mathe- 

 matical science, excepting perhaps chemistry and elec- 

 tricity, which has not been developed from the germs of 

 true scientific procedure which he disclosed in the ' Prin- 

 cipia' or the ' Opticks.' Overcome by the success of his 

 theory of universal gravitation, we are apt to forget that 

 in his theory of sound he originated the mathematical 

 investigation of waves and the mutual action of particles ; 

 that in his Corpuscular theory of light, however mistaken, 

 he first ventured to apply mathematical considerations to 

 molecular attractions and repulsions ; that in his prismatic 

 experiments he showed how far experimental verification 

 could be pushed ; that in his examination of the coloured 

 rings named after him, he accomplished the most remark- 

 able instance of minute measurement yet known, a mere 

 practical application of which by M. Fizeau was recently 

 deemed worthy of a medal by the Eoyal Society. We 

 only learn by degrees how complete was his scientific 

 insight ; a few words in his third law of motion display his 

 acquaintance with the fundamental principles of modern 

 thermodynamics and the conservation of energy, while 

 manuscripts long overlooked prove that in his inquiries 

 concerning atmospheric refraction he had overcome the 

 main difficulties of applying theory to one of the most 

 complex of physical problems. 



After all, it is only by examining the way in which he 

 effected discoveries, that we can rightly appreciate his 

 greatness. The ' Principia ' treats not of gravity so much 

 as of forces in general, and the methods of reasoning 

 about them. He investigates not one hypothesis only, 

 but mechanical hypotheses in general. Nothing so much 



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