376 THE WORLD MACHINE 



would eventually be found. This is always possible; but as 

 we have seen, it is highly improbable. 



So perhaps is the other inference that the universe is made 

 up mainly of double suns. The marvellous progress in late 

 years in photography of the nebulae seems to have spread before 

 our eyes the general course of stellar evolution. The images 

 which have been obtained of revolving nebulae present neither 

 the general type of a disk with a single centre of condensation, 

 nor that of a double centre, such as the binary arrangement 

 would suggest. Rather we find all types ; sometimes a single 

 central nucleus, sometimes a pair of nuclei, sometimes three 

 or four. 



For a long time we have known of stars that seem to be 

 triple, or even multiple. The larger part of these doubtless 

 are merely optically triple or multiple, and have no physical 

 connection. But we may infer that some of them do constitute 

 a system, and the photographic plate seems to reveal a quantity 

 of these triple and multiple systems in the actual process of 

 their evolution. This suggests readily enough that there is no 

 single type, no common mould, but that could we journey 

 through the stars, we should find a considerable variety, some 

 of them alone in solitary grandeur like our sun, some of them 

 sharing their thrones with a companion sun, others with dark 

 companions. There may be triumvirates and decemvirs, and, 

 for aught that we now know, conceivably centos and cinquecentos 

 that is to say, twins and triads and clusters and swarms. 



Of course, if there be aught in the idea of stellar evolution 

 and the nebular theory, and we have no other theory of creation 

 worth considering, there may have been a time when our own 

 system presented the appearance of a cluster of suns. The com- 

 panions of the central mass, however, are so insignificant, 

 even the greatest of them, Jupiter and Saturn, that they would 

 be all but invisible at the distance of the nearest known star. 

 But the telescope has revealed, as the photographs of nebulae 

 have suggested, that this partition of the mass of matter within 

 a system is not always so dismeasured. The separating masses 

 may be more nearly equal. 



We meet here with a perplexing problem. The fact that our 

 own system is made up of more than five hundred individual 

 bodies, the most of them, so far as we can see, in stable motion, 

 readily suggests that other flaming suns are likewise companioned, 



