66 



THE WORLD MACHINE 



are much longer than the nights, as in the northern summers, 

 for the other half of the world the days will be shorter, and 

 shorter by as much as they are longer in the northern hemi- 

 sphere. As you go toward one pole or other the condition 

 is intensified. 



So, when the sun is at the extreme point of its northern 

 advance, its summer halt or " solstice," as at S in the figure, 

 its rays will cover the northern pole ; from W, the winter 

 solstice, they will leave it in the dark. As this shifting of the 

 sun's position from one point to the other occupies half the 

 year it is clear that from the north pole (N P) the sun will 

 be continuously visible for six months and then for six months 

 disappear from sight. When the sun stands at E there will 



FIG. i. 



Note. It is needless to say that this scheme is based on the idea that 

 the sun circles the earth, as it so doubtless appeared to Bion. 



be equal nights and days all over the earth, save at the ex- 

 tremities of the poles. This is our equi-noctes, period of storms. 



Here, then, was a geometrical construction which accounted 

 for all the facts of observation. But to do so absolutely there 

 was a difficulty to be surmounted. The theory of Bion re- 

 quired that the sun be at such a distance that the bulk of the 

 earth cuts no figure. For it is clear enough that if the earth 

 is very large, and the sun a small body not so very far away, 

 the curve in the earth's surface would shut off the sun's rays 

 from much more than half the earth, and no day anywhere 

 would be twelve hours long. In order that the day occupy 

 one-half the time from one dawn or one sunset to the next, 

 the sun must illuminate half the earth, provided, of course, 

 that the earth is really round. And there was no escaping the 

 evident certainty of this last. 



More than that, the shadow that falls upon the moon in 



