282 The Glacial Epoch . [May, 
this to have been once at London ; at the same time the evi- 
dence is not entirely satisfactory to show the world was once 
entirely tropical, or entirely glacial, so that we may fairly 
conclude that the polar axes have oscillated at any rate over 
a much wider range than at present. Darwin himself seems 
puzzled (“ Origin of Species,” Chap. XI., p. 368) when he 
explains “ that there is enough to show that it is almost 
demonstrable that what are now the ArCtic and Temperate 
Zones have known a warmer climate than the present ” 
(even) “ since the Glacial Period.” How utterly impossible 
had the Poles always been the same. One step further, and 
the whole matter appears clear as daylight ! The existence 
of northern (Alpine) forms beyond the Equator is proof 
positive that the “ North Pole ” must have “ crossed the 
Line,” or vegetation been driven concentrically over it, when 
there was no South Pole, which would further explain why 
the northern vegetation is not so thoroughly dominant in 
the south ; for as the South Pole turned out of the Sun’s 
radius only one part of the northern cap of ice would push 
south, whilst the other parts retreated north, and then the 
South Pole would gradually form a colder and wider nucleus. 
This would especially be effective if it were possible the 
Earth had no diurnal motion. Of course in the case I am 
supposing the Torrid Zone (at the South Pole) would know 
no night : this would vastly increase vegetative growth. 
Recent experiments with electricity have apparently demon- 
strated the faCt that plants will continue to grow in the 
“ night time ” under the bright light of electricity, and 
gain on their contemporaries; so that it would not mean the 
destruction of vegetation, the air being filled with aqueous 
vapours, &c. But there is no need to suppose that this ever 
really took place. We must bear in mind that this South 
Pole would have been at all parts of the world. Again, 
Darwin says (Chap. XI., p.371) “ the productions of Europe 
and America during the late Tertiary Stages were more 
closely allied to each other than at the present time.” This 
would be a time before a Glacial invasion upset the equal 
evolution. Chap. XL, p. 373, states that evidence of glacial 
aCtion is visible over Europe from the Pyrenees to the Oural, 
in Siberia, the Himalayas, New Zealand, South-east Aus- 
tralia, the Cordillera in Chili, and so forth. “We have 
also excellent evidence that it endured for an enormous 
time, as measured by years at each spot.” It is more to 
the point when he says “ It should be observed that the 
northern forms found in the southern parts of the Southern 
Hemisphere, and on the mountain ranges of the Inter- 
