34 
coal flora, or upon our tropical animals, but we have plenty 
of evidence in every ancient record. 
But this is not all. We observe in the whole of Nature's 
works, an analogy. We see that all the planets are spherical, 
or nearly so ; that they all move around the sun ; that they all 
rotate upon their axis ; that they are, in fact, like one family. 
If, then, the tropics ever extended to the northern and 
southern portions of the earth, should we not find some other 
planets in a similar state now. Surely we might expect such 
a circumstance ; and we have but to examine for ourselves if 
we doubt the observations of other astronomers, and we shall 
see, as is even now well known, that in Mercury the tropics 
do at the present time extend to within a very few degrees of 
his poles. In Yenus the tropics are now within 15° of her 
poles. In the Earth 23° 27' from her equator, whilst in 
Uranus the tropics again it is supposed extend to her poles. 
(See Plate II.) 
Thus we have our tropical remains, the records of men 
who lived on earth when such facts existed, and the whole 
analogy of the solar system, to prove that the tropics did 
once extend to the poles. 
And what have we to disprove the fact ? Well may we ask 
what ; there is really nothing save the superstitious belief 
that every fact in astronomy was long ago discovered, and 
that since the days of Newton, nothing can be wrong. For 
a very long period there was popery in religion, let us beware 
lest superstition lead us to popery in science — a much more 
retarding proceeding. 
It can now be shown, that the variation which has taken 
place in the position of the fixed stars since the time of 
Hipparchus, which variation still continues, and is accurately 
recorded in the Nautical Almanac, as well as the precession of 
the equinox, shows that the third movement of the earth is, a 
SLOW INVERSION OF ITS POLES IN A PLANE WHICH IS 
