CHAPTER V 



Colligative Relations and 

 g\C47n^ Scieivtific Laws 



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BRARY 



MASS. 



OME colligative relations plainly 

 arise from everyday experience ( e.g., "Two things cannot occupy the 

 same place at the same time"); others are uniquely the products of 

 science (e.g., Boyle's law). Some are qualitative ("Metals resemble 

 each other in their physical properties" ) ; some are statistical ( Men- 

 del's genetic ratios); some yield precise quantitative predictions 

 ( Moseley's law ) . Some are exact to the limit of our capacity to check 

 them experimentally (the law of the lever); most meet the test of 

 experience only approximately (Kepler's first and second laws of 

 planetary motion ) . They range continuously from what appear to be 

 no more than definitions ("Sulfur is a yellow crystalline solid . . ."); 

 to almost purely mathematical theorems ("In the space of our ex- 

 perience the sum of the angles of a triangle is 180°"); to what may 

 appear no more than conventions (Galileo's law of free fall). Some 

 are obviously of restricted applicability ( the Bode-Titus law ) ; others 

 ( the equivalence of gravitational and inertial masses ) seem to be of 

 extreme generality. 



Relations multifarious as these presumably fall in separable sub- 

 groups. However, the present purpose is to show that— their over- 

 whelming di\ ersity notwithstanding— all share enough in common 

 amply to justify grouping them together, as colligative relations. 



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