143 



[Chase. 



Dulong D 1015.97 miles. 



Hess H 1017.40 " 



Crawford C 1052,73 " 



Grassi G 1013.72 " 



Favre and Silbermann. . . F 1013.G0 " 



Adams A 988.63 " 



Mean of D, H, G, F 1015.18 " 



General Mean 1017.01 " 



If we assume the correctness of the general mean, d = ^X V~8~ ~ 

 1129.61 : r ' 5 = -' 5 X V — = 578.5 X-- 29 ' 61 - = 82.45 seconds ;«_<{-*- 



' 1 ^ \ (1 ^ 7925.64 



(J 7925.64 



4 = 282.4 ; T (l =e 



96.515 seconds ; <o = 2 -x~l d = 



Id 



18.3844 miles ; T/ = v X 1 year (in seconds) --2^ =92,338,000 miles ; 

 ,, = y/ h- X = 326,980. 



This approximation is subject to correction for possible imperfect elas- 

 ticity of hydrogen, tethereal resistance, and orbital eccentricity. From 

 various considerations I am inclined to believe that the aggregate cor- 

 rections for the value of r, cannot exceed to one and a-half per cent, of 

 the above amount. 



NOTE ON PLAXETO-TAXIS. 

 By Pliny Earle Chase. 



(Read before the American Philosophical Society, March 7th, 1873.) 



I am not aware that any reason has ever been assigned for the planetary 

 harmony which is formulated in "Bode's Law," or that any attempt has 

 been made to show that the failure of the analogy, in the case of Nep- 

 tune, is really only one of those apparent exceptions which serve to 

 establish general rules on a firmer basis. 



The many evidences which I have already adduced, of simple relation- 

 ships between planetary positions and centres of oscillation, seem to 

 furnish the needed data for verifying the law, as a simple and natural 

 resultant of equilibrating forces, and not a mere accidental coincidence. 

 If a nebulous mass were set in rotation, each of its equatorial radii might 

 be regarded as a simple pendulum, with a tendency to vibrate in the same 

 time as its centre of oscillation, which tendency might be expected to 

 produce an aggregation at that centre. 



If we start from the circularly divided radius next within the orbit of 



Mercury, {* r = .0982], and add multiples of the next following radius 

 (?_ r = .3085], we may form the first series (A) in the following table, 



