NEW CONCEPTIONS IN SCIENCE 



the nature of the mind. We are unable to con- 

 ceive bounds to space ; nor can we picture an object 

 so small that it cannot be again divided; nor can 

 we think of anything going so fast that nothing 

 could go faster. Nevertheless, limits do seem to 

 exist. The bounds and speeds and units of the uni- 

 verse all seem measurable quantities. They are, 

 therefore, finite and not infinite. I shall try to 

 give, in the briefest way, the evidence on which this 

 view is based. 



There are two reasons, at least, for believing that 

 the stellar universe is not boundless. The first of 

 these is grounded on the theory of light. We are 

 aware of the existence of the stars only through 

 their ability to affect the retina or the photographic 

 plate. The light they send us is mainly white, that 

 is to say, compound. It is a mixture of all the col- 

 ors of the rainbow, and each of these colors repre- 

 sents a different wave-length. In passing through 

 ordinary substances, like glass or water, the differ- 

 ent colors are differently impeded or absorbed. If 

 the light from the pole -star passed through an 

 absorbing medium on its way to the earth, it is 

 likely that the absorption would be, in some de- 

 gree, selective. One color would be more absorb- 

 ed than another. The light from the stars would 

 not be white; it would be tinted. There are, of 

 course, red stars, like Orion, yellow stars, like Arc- 



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