NOVUM ORGANUM 413 



to masses or aggregates which resemble them, the light towards 

 the heaven, the heavy towards the earth; and all this is very 

 fine language. 



But we have an instance of alliance in low comets, which re- 

 volve, though far below the heavens; and the fiction of Aris- 

 totle, of the comet being fixed to, or necessarily following some 

 star, has been long since exploded ; not only because it is im- 

 probable in itself, but from the evident fact of the discursive 

 and irregular motion of comets through various parts of the 

 heavens. 



Another instance of alliance is that of the motion of air, 

 which appears to revolve from east to west within the tropics, 

 where the circles of revolution are the greatest. 



The flow and ebb of the sea would perhaps be another in- 

 stance, if the water were once found to have a motion of revolu- 

 tion, though slow and hardly perceptible, from east to west, sub- 

 ject, however, to a reaction twice a day. If this be so, it is clear 

 that the motion of revolution is not confined to the celestial 

 bodies, but is shared, also, by air and water. 



Again the supposed peculiar disposition of light bodies to 

 rise is rather shaken ; and here we may find an instance of alli- 

 ance in a water bubble. For if air be placed under water, it rises 

 rapidly towards the surface by that striking motion (as Dem- 

 ocritus terms it) with which the descending water strikes 

 the air and raises it, not by any struggle or effort of the air itself ; 

 and when it has reached the surface of the water, it is prevented 

 from ascending any farther, by the slight resistance it meets 

 with in the water which does not allow an immediate separation 

 of its parts, so that the tendency of the air to rise must be very 

 slight. 



Again, let the required nature be weight. It is certainly a 

 received classification, that dense and solid bodies are borne to- 

 wards the centre of the earth, and rare and light bodies to the 

 circumference of the heavens, as their appropriate places. As 

 far as relates to places (though these things have much weight 

 in the schools), the notion of there being any determinate place 

 is absurd and puerile. Philosophers trifle, therefore, when they 

 tell you, that if the earth were perforated, heavy bodies would 

 stop on their arrival at the centre. This centre would indeed 

 be an efficacious nothing, or mathematical point, could it affect 

 bodies or be sought by them, for a body is not acted upon except 

 by a body. In fact, this tendency to ascend and descend is either 

 in the conformation of the moving body, or in its harmony and 

 sympathy with another body. But if any dense and solid body 

 be found, which does not, however, tend towards the earth, the 

 classification is at an end. Now, if we allow of Gilbert's opin- 

 ion, that the magnetic power of the earth, in attracting heavy 



