1880.] 4-j7 [Chase. 



■v.\ 2 

 would transmit undulations with the velocity of light, is i K | ,"<>. This is 



equivalent to f __ yp n = 474,500,° . For v., as we have already 



\. 000625(53/ ° A 



seen, is .43096/' o , and eu is 2 JWX (2*4-54); 2 ^ _ . 0062563,° . If 



365.256 X 86400 ^s 



the cyclical variations of alternately increasing and diminishing stress, to 

 which every particle of the Sun is exposed during each half- rotation, are 



due to the velocity of light, the equations, ?5_* = v., and V g p = .0006- 



2563^, give : 



g — .00000039142« ~\ 



t = 2 * • 43096 ^o = 2,202,050 sec. = 25.486 dy. < 8 -> 



9o J 



The continual disturbances at Sun's surface, and the combined influences- 

 to rotation and revolution upon spots near the solar equator, make it im- 

 possible to rind the exact value of t Q by direct observation. Laplace's esti- 

 mate was 25^ days ; Carrington's 25.38 days. According to his observa- 

 tions, ; ' near the equator the period was about 25.3 days, while it was a.day 

 longer in 30° latitude. Moreover, the period of rotation seems to> be dif- 

 ferent at different times, and to vary with the frequency of the spots. But 

 the laws of these variations are not yet established. In consequence of their 

 existence, we cannot fix any definite time of rotation for the Sun, as we 

 can for the Earth and for some of the planets. It varies at different times, 

 and under different circumstances, from 25 to 26^ days." * 



It is, therefore, impossible now to assign any more probable value to 

 t than the one which I have deduced theoretically from the stress of lumi- 

 nous waves. If future observations should lead to the acceptance of a 

 period which is either slightly less or slightly greater, the discrepancy can 

 be easily accounted for, either by orbital acceleration or by inertial resist- 

 ance and retardation. 



If fa represents Stockwell's determination of the centre of the belt of 

 greatest condensation (1. 016878,°,, = 218.16,° ) and if we suppose a simi- 

 larity of action and reaction at the nucleal centre (Sun's centre == c ) and 

 at the dense-belt centre (c o ), we find : 



gy 



■s)'-iS x l 



i 



(474500 x 1.016878 x 214.54)* = 366.256^ 



&3 



g = S7.78&. j. (9)) 



p = 9*°* r s = 27. 783X. 9175X3962.8 = 431,230 miles. 



ff» d o 

 p 3 = 214.54/> = 92,520,000 miles. 



v = 185,850 miles. 

 *Newcomb : Popular Astronomy, p. 2-50. 



