Chase.] . 40U [June 17, 



reaction against setliereal action (G^ T^) is tlie velocity of liglit (i\). Tliere- 

 fore, if v^ and v^^ are primitively synchronous, designating Earth's semi- 

 axis major by p^. 



Sun's mass (/ij : Earth's mass {,1,^) : : v^ : \ : : 407 007 '■ -56558 miles. . (1) 

 If we designate Sun's and Earth's densities, respectively, by d^ and ^3. 



/ PS Y 



/J-o ■ /J-3 ■■ ■■ V, 214745/ '^0 : -^3^ ^3 (2) 



S3:8o--\^- A^V : (2 TT ^iJJ : : (10049)^ : (5073. 6)^ : : 1 : .2549. . (3) 

 Substituting (3) in (2) we find, by elimination between (1) and (2), 

 _„„ = 328,424,,.3. 

 ^3 = 92,472,100 miles. 

 r„ =^3 -- 214.45 = 431,206 miles. 



57. GonmrtihilUy of Natural Units. 



Stoney's notation, with the modifications proposed in Note 47, connects 

 the electric and photic units through the equation : 



1^3 = L„ - T„ = I - i = e - E = (C ^ c)^ = (r - R)*. 

 The gravitating, photic, thermal and electric units are, therefore, inter- 

 convertible by the equation 



G^T„ — v^ — — v^ = i}^— 185,751.6 miles == 298,930 kilometres. 



fJ-3 



It seems probable, in view of the mean result of my other physical in- 

 vestigations, that . the above values of //„ and p^ may be, respectively, 

 about one per cent., and ^ of one per cent., too small. If the calorie and 

 J were estimated at the equator, the approximation would probably be 

 still closer and, perhaps, exact. 



58. Sola?' Temperature. 

 The infinitely projectile or radiating power of a central mass varies as 



■y/2 gr OC A/ — . When the comi^arison of mutual solar and terrestrial ac- 

 tions and reactions is made through their common radius or semi-axis major, 



A/ — oc i//-^ OCA/--. As i\ is the thermal equivalent-velocity at Earth's 

 surface for 100° C, we may infer that the mean radiating temperature, 



at Sun's surface, is ^3 X 100^ X 1/328,424 = 27.739 X 57308° = 1589590° 



r 

 C. The temperature deduced from Sun's semi-diameter (rj is i qqq 3 f> 



= 1638430° C, being 1.0307 times the value which is indicated by the 

 mutual actions and reactions of solar and terrestrial mass. This approxi- 



