i9o6.| SEE— THE CAUSE OF EARTHQUAKES. 287 



II. On the Porosity of Matter and on the Leakage of the 



Ocean Bottoms. 

 § 5. Oil the porosity and penetrability of matter under the enor- 

 mous Hiiid pressure operating in the deepest oceans, and the under- 

 lying crust of the earth. 



Somewhat extensive researches on the internal pressures, con- 

 stitution, and rigidities of the sun and planets, carried out during 

 the past two years and published in the Astronomische Nachrichten, 

 have led the writer to the conviction that many of the laws of matter 

 depending on molecular forces, such as impenetrability and solidity, 

 are quite inapplicable to the conditions prevailing in the interior of 

 the earth and other bodies of our solar system ; that under the 

 immense pressures there operating, whatever be the temperatures, 

 but especially under the high temperatures known to prevail in the 

 interior of these masses, the hardest natural bodies would yield 

 like sponges, and admit of the most perfect interpenetrability of 

 all the elements. The conclusion was reached from the study of 

 forces of somewhat impressive magnitude that all matter is enor- 

 mously porous, and quite leaky under forces much smaller even than 

 those operating in the interior of the earth ; so that solidity and 

 impenetrability, long held to be among the most universal properties 

 of matter, far from being absolute, appeared to be very relative 

 properties, appropriate to very small, but wholly inappropriate to 

 larg:e, forces, and sometimes set aside bv the direct evidence of our 

 senses in common laboratory experiments. 



There doubtless are many experiments which would enable us to 

 appreciate the significance of these general principles in specific 

 cases, but it will suffice to recall one close at hand, and directly 

 connected with the question under discussion. In the series of 

 soundings of the depths of the sea carried out some years ago by 

 certain officers of the United States navy occupied with hydrographic 

 and ocean surveys it was found that hollow glass balls with walls 

 several centimetres thick, when subjected to increasing pressure at 

 various depths, came up more and more completely filled with water, 

 in proportion as the depth increased, though no fracture of the 

 glass had occurred, and no holes in it could be discovered by ex- 

 amination of the surface under the highest microscopic power. 



