46 COSMOS. 



elusion to be drawn from these facts is, that in general planets 

 and other sidereal masses which, by the influence of a central 

 body, have been agglomerated into rings of vapour, and sub- 

 sequently into spheroids, being integrant parts of the same 

 system, and having one common origin, may likewise be 

 composed of substances chemically identical. Again, experi- 

 ments with the pendulum, particularly those prosecuted with 

 such rare precision by Bessel, confirm the Newtonian axiom, 

 that bodies the most heterogeneous in their nature (as water, 

 gold, quartz, granular limestone, and different masses of 

 aerolites) experience a perfectly similar degree of accelera- 

 tion from the attraction of the earth. To the experiments of 

 the pendulum may be added the proofs furnished by purely 

 astronomical observations. The almost perfect identity of the 

 mass of Jupiter, deduced from the influence exercised by this 

 stupendous planet on its own satellites, on Encke's comet of 

 short period, and on the small planets Vesta, Juno, Ceres, and 

 Pallas, indicates with equal certainty, that within the limits of 

 actual observation attraction is determined solely by the 

 quantity of matter.* 4 



This absence of any perceptible difference in the nature of 

 matter, alike proved by direct observation and theoretical 

 deductions, imparts a high degree of simplicity to the me- 

 chanism of the heavens. The immeasureable extent of the 

 regions of space being subjected to laws of motion alone, the 

 sidereal portion of the science of the Cosmos is based on the 

 pure and abundant source of mathematical astronomy, as is 

 the terrestrial portion on physics, chemistry, and organic 

 morphology ; but the domain of these three last-named 

 sciences embraces the consideration of phenomena which are 

 so complicated, and have, up to the present time, been found 

 so little susceptible of the application of rigorous method, that 

 the physical science of the earth cannot boast of the same 



Connecticut, gave the following results : Oxide of iron 24 ; oxide of 

 nickel, 1'25; silica, with earthy matter, 3'46; sulphur, atrace; = 28'7l. 

 Dr. Mantell's Wonders of Geology. 1848. vol. i. p. 51.] 2V. 



* Poisson, Connaissances des Temps pour I'Annee 1836, pp. 64 66. 

 Bessel, Poggendorff's Annalen, bd. xxv., s. 417. Encke, Abhandlungen 

 der Berliner Academie, (Trans, of the Berlin Academy,) 1826, s. 257. 

 Mitscherlich, Lehrbuch der Chemie, (Manual of Chemistry,) 1837, 

 bd. i., s. 352. 



