110 TWO NEW WORLDS 



Can it be that gravitation becomes 10 33 times 

 feebler than it is in more accessible places ? Upon 

 an answer to this question depends any real progress 

 we may make in our demonstration of a supra- 

 world. At present we can only indicate two or 

 three alternative probabilities, one or the other of 

 which is more probable than the rest. 



The argument from gravitation is so ingenious 

 and comparatively new, that it will, perhaps, be 

 useful to state it in full and in simple language. 



Let there be only two bodies in space, one about 

 the size of the sun, and having a mass of 10 33 

 grammes, and the other a mass of 1 gramme, 

 situated at a practically infinite distance, so far 

 away that the attraction between them is im- 

 measurably small. Now let the gramme fall 

 towards the sun. Its velocity, at first excessively 

 slow, will gradually increase, and its acceleration 

 will also increase as it approaches the sun and 

 the force between them increases. To calculate 

 the actual speed of the gramme at any given 

 distance from the sun may appear a task of for- 

 midable difficulty, and requiring high mathematical 

 training. But it is made really very simple by the 

 theory of potential, which plays such an important 

 and useful part in the science of electricity. 1 



Take the limit of 10,000 light-years or 10 22 cm., 

 and suppose, with Lord Kelvin, that a sphere of 

 1 See Note B at end of this chapter. 



