Geology, as illustrated by Chemistry and Physics. Ah 



ever exterior configuration the forces acting upon it might 

 tend to produce. This was confirmed by experiment ; for the 

 mass of oil, however large it might be, always assumed a 

 perfect spherical figure while floating in the alcoholic liquid, 

 and, as it were, imitated one of the planetary bodies suspended 

 in cosmical space. By means of a simple centrifugal machine, 

 Plateau succeeded in causing such a sphere of oil to rotate, 

 and found that it became flattened at the poles, and spread 

 out at the equator. When a considerable velocity was given 

 to the sphere, it rapidly assumed the maximum of flattening, 

 then it became hollow round the axis both above and below, 

 and continued to extend more and more in a horizontal direc- 

 tion. Finally, it changed into a perfectly regular ring, and 

 resembled that of Saturn. By modifying the experiment, he 

 even succeeded in making a sphere of oil remain in the in- 

 terior of the ring. Still Plateau recognised nothing more in 

 this experiment than a scientific curiosity ; for the circum- 

 stances which determined the result had evidently no simi- 

 larity with those which have contributed to the formation 

 of Saturn's rings. 



Thus both theory and experiment lead to the inference 

 that the earth and other planets have been formed from 

 liquid masses. If there were a common solvent for all the 

 substances existing upon the earth, it might be conceived 

 that they had existed in such a solution at the creation. But 

 such an assumption would be in contradiction to chemical 

 laws. And as the assumption of an aqueous pasty condition 

 is likewise an hypothesis which has but little foundation, 

 there remains only the condition of igneous liquidity which 

 is probable. 



In favour of this, there are also analogies in the meteoric 

 stones. If these, as Chladni conjectures, are older forma- 

 tions, which have long existed in some form or other in cos- 

 mical space, or if they have originated from pre-existing 

 materials, only a short time previously to their falling, the 

 view that they are of cosmical origin is the most probable of 

 all those which have been contrived for their explanation. 

 According to all observations, they reach our earth in a more 

 or less heated state — sometimes even red-hot. Many pre- 



