17. 



1 0^ 

 186i).] -'-'^^ [Chase. 



In the orbital motion tlie pressure of solar force is nearly constant, but 

 terrestrial gravity tends to maintain the atmospliere at a uniform level, 

 or in a constant volume. Now the kinetic energy under constant pres- 

 sure : that under constant volume : : 1.421 : 1, or very nearly : : y 2 : 1. 



M. Treves found that the number of oscillations in a tuning fork was 

 increased j|y by magnetizing the fork. Farther experiments are desir- 

 able to determine whether his result may be accepted as a general one, 

 but it may be temporai-ily regarded as curiously coincident with our 

 hypothetical case, in which 



*• '"'•'• v' 2m : V to' 

 817: 1 : : y2my : V lUi 



18. I 3wi : V m^ : : sp. gr. water : sp. gr. air (at mean tempera- 

 ture) 



19. (^2to, )*: ( 7«4 )^ -91 -ffi 



20. 2g,t,X I' = V4 



21. The inertia of the air which is retarded by the thermal and 

 tidal "brakes" appears to be overcome and the wave-equilibrium re- 

 stored, after g^ has acted for a sufficient time to give V^. 



/ veai'lv \ ^ 



22. ^-^ "" ( ri -1 b^''o™etric range ) at St. Helena x Si h ^ 



23. 2i 2™" X [e,]' : V'm, ••■g^-.g.X (^-£) 



24. Mean vel. of sound = mean vel. of air. 



25. If ^ be divided in proportion to the i of the several planets, 



Jupiter's proportion will be /. of 1125.84 = 692.83, and 692.83 x Vi = «• 

 It may be desirable to modify some of these equations by considerations 

 connected with centrifugal force. The closeness of the principal analo- 

 gies may be illustrated by a few examples, in which I assume the following 



values as a basis of comparison : A ' - = 1.449662; / ri= 5.630334 .•. Xh= 



m, 

 11.302517 ;— and Newcomb's estimates, ^ = 326,800: d^ = 92,380,000 ; v 



= 185,600. 



Sporer. Faye. Carrinston. Kirkwood. Theory. Mean. 



1. ti = 24.62447 dy. 25.07472 dy. 24.9711 dy. 24.S2594 dy 25.0297 dy. 24.90.52 dy. 

 .-. M = 188,697 m. 185,267 m. 186,035 m. 187.123 m. 185,600 m. 186,528 m. 



Theoretical. Assumed. 



Q d,., 30.070552 A 



'• Sr--387098r ■■■-^«8,770 465,604. 



4. -^ = 682.3516 .-. ^' = 3.1416 3.158. 



A. P. S. — VOL. XI — N 



