ORGANIZATION OF THE SCIENCES 



ference in the rates of a clock at the equator and 

 nearer the poles gave data for calculating the 

 oblateness of the earth, and accounting for the 

 precession of the equinoxes. It was thus — but 

 it is needless to continue. We have already 

 named ten cases in which the single science of 

 astronomy has owed its advance to sciences 

 coming after it in Comte's series. Not only its 

 secondary steps, but its greatest revolutions have 

 been thus determined. Kepler could not have 

 discovered his celebrated laws, had it not been 

 for Tycho Brahe's accurate observations ; and 

 it was only after some progress in physical and 

 chemical science that the improved instruments, 

 with which those observations were made, be- 

 came possible. The heliocentric theory of the 

 solar system had to wait until the invention of 

 the telescope before it could be finally estab- 

 lished. Nay, even the grand discovery of all — 

 the law of gravitation — depended for its proof 

 upon an operation of physical science, the mea- 

 surement of a degree upon the earth's surface. 

 Now this constant intercommunion, here illus- 

 trated in the case of one science only, has been 

 taking place with all the sciences. . . . Let us 

 look at a few cases. The theoretic law of the 

 velocity of sound, enunciated by Newton on 

 purely mechanical considerations, was found 

 wrong by one sixth. The error remained un- 

 accounted for until the time of Laplace, who, 

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