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plane of the ecliptic, as is indicated further on in Figs . XC.and XCI., the planet’s equator and the orbits of its satelliteswould become nearly perpendicular to that plane.
Let us, however, for a moment or two suppose the coinci-dence of the planet’s axis with the ecliptic to he exact, andconsider the exceedingly remarkable results which wouldfollow. They would, of course, be such as would exist uponthe Earth , if its polar axis were, in like manner, in the planeof the ecliptic, instead of being inclined to it at an angle of661r°. It is easy to understand that the peculiarities of thepolar regions would under such circumstances extend over thewhole of the Earth , as would also those of the tropics ; thearctic circles would be brought down to the equator, andthe tropics of Cancer and Capricorn would be moved up tothe poles.
At the poles the sun would remain visible as at present forsix months at a time, but in the height of summer it would bevertically overhead at noon ; while for three mouths after thespring equinox it would describe a spiral curve in the sky,first going round close to the horizon, then gradually ascending-higher, and travelling day by day in smaller and smaller circles,until it would be nearly fixed in the zenith on the day of thesummer solstice and for some days before and after that date.Upon one-half of the globe the days would increase from 12hours in length at an equinox, until, at the summer solstice, thewhole hemisphere would see the Sun during a day of 24 hours.Upon the other half the nights would increase in like manner,until at the winter solstice they would be 24 hours long, andthe Sun would be invisible for the whole of the day throughoutthe hemisphere in question. At places near to the equator,when the days would be longest, the Sun would all through theday keep very close to the horizon, since it would go round thepole of the heavens, which would itself be so situated, in a verysmall circle ; just as at places near to the poles, it would, at thesame time, appear to go round the celestial pole, in a similarsmall circle, near to the zenith.
All this may be easily worked out, by imagining the globe ofsuch a planet to circuit round the Sun while keeping its axis