Tro\vbrid;;c.J 



332 



[Nov. 3, 



pmximation to the trutli. Equation (23) is independent of any supposition 

 in relation to tliis matter. 



n. In ilie following table I have arranged the various elements of the 

 planetary atmospheres, which luive been tlie subject of the foregoing inves- 

 tigation, on the supposition that K = 1, and to = 0. 



The last column of this table, or that which gives the hight of the at- 

 mosphere, is based upon the supposition that the exterior limits of the plan- 

 etary atmosphere have the same density for all, and that the Earth's atmos- 

 phere has a hight of 343 miles. It is not a little curious at first sight that 

 Jupiter's atmosphere should be the least extensive in hight. while Mars's is 

 the most extensive ; but this is due to the great attractive influence of the 

 one, and the smallne.ss of the same element in the other. Though this ta- 

 ble is l)ased on an unc(?rtain hypothesis, j^et it seems to me that it is con- 

 siderably instructive. Besides, the preceding theory will serve to test 

 some of the hypotheses which are offered to account for the surface appear- 

 ances of Jupiter. 



The peculiar figure which Sir William Herschel found Saturn to present, 

 which Bessel and others could not discover, and which Airy could not ex- 

 plain upon the theory of gravitation, is accounted for without difficultj' by 

 the currents in his atmosphere, as will be seen by consulting Wm. Fer- 

 rel's Treatise on the Mot'on of Fluids relative to the Earth's Surface, 

 Art. 18, Fig. 1, Vol. I, Math. Mon.thly; and if Jupiter's atmosphere were 

 sufficient!}' extensive he ought to present a similar figure. 



Waterbrircjh, N. ¥., October 19, 1876. 



NOTE. 



Since the above was written I have seen a report of Prof. S. P. Langley's 

 experiments to determine the temperature of the solar surface. Physicists 

 have heretofore ditlered considerably in their estimates of the Sun's tem- 

 perature, Secchi putting it as high as 18 millions of degrees Fah., St. Claire 

 Deville and others, between 3,000° and 20,000^. Prof. Langley's result 

 favors the higher number. For convenience of calculation let us assume 

 the solar temperature etpial to 9,800,032° Fah., so that /to = 20,000. 



Now let A'.— 1, then we find, by Equation (19), A = 0.0369^0 ; or the 



