152 NOVUM ORGANUM. 



inaccuracy of the return, and declination to the tropics may be 

 rather modifications of the one diurnal motion than contrary 

 motions, or about different poles. And it is most certain, 

 if we consider ourselves for a moment as part of the vulgar 

 (setting aside the fictions of astronomers and the school, 

 who are wont undeservedly to attack the senses in many 

 respects, and to affect obscurity), that the apparent motion 

 is such as we have said, a model of which we have some 

 times caused to be represented by wires in a sort of machine. 



We may take the following instances of the cross upon 

 this subject. If it be found in any history, worthy of credit, 

 that there has existed any comet, high or low, which has 

 not revolved in manifest harmony (however irregularly) with 

 the diurnal motion, then we may decide so far as to allow 

 such a motion to be possible in nature. But if nothing of 

 the sort be found, it must be suspected, and recourse must 

 be had to other instances of the cross. 



Again, let the required nature be weight or gravity. Heavy 

 and ponderous bodies must, either of their own nature, tend 

 towards the centre of the earth, by their peculiar formation; 

 or must be attracted, and hurried, by the corporeal mass of 

 the earth itself, as being an assemblage of similar bodies, 

 and be drawn to it by sympathy.* But if the latter be the 

 cause, it follows that the nearer bodies approach to the 

 earth, the more powerfully and rapidly they must be borne 

 towards it, and the further they are distant the more faintly 

 and slowly (as is the case in magnetic attractions), and that 

 this must happen within a given distance, so that if they 

 be separated at such a distance from the earth that the 

 power of the earth cannot act upon them, they will remain 

 suspended like the earth, and not fall at all. 



The following instance of the cross may be adopted. 

 Take a clock moved by leaden weights, and another by a 

 spring, and let them be set well together, so that one be 

 neither quicker nor slower than the other ; then let the 

 clock moved by weight* be placed on the top of a very high 

 church, and the other be kept below, and let it be well ob 

 served, if the former move slower than it did, from the 

 diminished power of the weights. Let the same experiment 

 be made at the bottom of mines worked to a considerable 



* A. close approximation to the truth and the experiment pointed out is very 

 ingenious ; indeed the oscillations of the pendulum, moving by its own weight, 

 have since been used as the most delicate tests of the variation of gravity from 

 the equator towards the poles. 



