NOMOS. 145 



such a matter. What to repeat a former question 

 is heat ? Is it not the sign of that law which, 

 according to the premises, is impressed upon all 

 things, and which rules the action of the moon upon 

 the earth as it rules the action of the sun upon the 

 earth? And if it is, then the thermometer is too 

 coarse a test for the more delicate degrees of heat, 

 and for these we must rather have recourse to the 

 mile-long galvanometric coil of Du Bois-Beymond, 

 than to the tube of Fahrenheit. According to these 

 views, indeed, the lunar ray can be no more divested 

 of the idea of heat than the solar ray, and this is 

 one point gained, for if there is any heat in the ray 

 there is in all probability enough for our purpose. 



In speaking upon the action of solar heat upon 

 the earth, we assumed the case of an imaginary 

 earth of solid granite, and found that the radius 

 would expand to no less than 1209 feet for every 

 degree of Fahrenheit. And if so, does it not follow 

 that a very small part of a degree may be sufficient 

 to expand the earth to that small extent to which 

 the earth is supposed to rise above the waters in the 

 case of the tides, a part so small, perhaps, as to 

 be as far beyond the detective capabilities of the 

 mile-long coil, as the capabilities of the coil are 

 beyond those of the common thermometer ? There 

 can be no doubt as to this ; and if there cannot, then 

 there is no difficulty in supposing that there is 

 enough power in the lunar ray to cause the tidal 

 expansion of the earth. 



But how is it that the moon acts more energeti- 

 cally than the sun in producing the tidal expansion 



L 



