Corpus of Electronic Texts Edition
An Irish Astronomical Tract (Author: [unknown])

Caibidil 36



The ancients imagined a line through the middle of the earth directly from the east of it to the west co-incidental with the equinoctial line, and they handed it down to us that that line is equidistant from the Arctic and the Antarctic Poles.

Between that line205 and the Arctic Pole is the habitable part of the earth, although that entire portion is not habitable. No living thing on earth can exist from the same line to the Antarctic Pole, on account of the excessive heat. Because, since it is in the eccentric sphere that the body of the sun is borne around the earth, and since that sphere inclines towards that side, that side of the earth must necessarily be much hotter than any other, and the heat which is on that side scarcely exceeds the cold which is on the other side opposite it. Consequently, at the extreme northern portion of the earth, on account of the great distance of the sun from it, there is nothing but many dark clouds and much wind and rain, frost, snow and excessive cold. On that account that place is uninhabitable, and the part which is along the equinoctial line temperate.

The days and nights of the year are exactly of equal length in that place. The portion of the earth which is habitable extends from that line along the equinoctial as far as the uninhabitable district in the north. The ancients


divided that portion into seven parts in all, from the east of the earth to the west, as this figure demonstrates.


Concerning the nature of those lands:

From the line along the equinoctial begins the first zone as regards latitude, and extends in longitude, as I mentioned, from the east of the world to the west. And the whole day does not exceed twelve hours and two-thirds exactly twice a year, and is not shorter than eleven hours and one-third. Twice in the year the sun passes (directly) over the inhabitants of that region, i.e., when it moves from the south of the firmament to the north, and from thence to the south again; consequently, there are two summers in one year in that region. In that region, from north to south of it, the shadow never inclines.

The nature of the second zone:

The excessive amount of the sand of that region makes it too warm, because the heat of the sun penetrates the sand, and scorches and burns the surface of the earth; and when a high wind comes it collects the sand and forms hills and mountains from it and at another time scatters it. The inhabitants of that region


are black people called "Negroes,"207 with curly hair. There is a great abundance of gold in that region, because the very great heat of the sun parches the surface of the earth. Not in the veins and hollows of the earth is the gold found, as are silver, tin and other metals, but on its surface. Day never exceeds thirteen hours, or is less than twelve hours in that region208.

The nature of the third zone:

The heat of these regions is less than that of the previous one because the sun is never directly above except for a short time in the summer solstice, and that climate is more temperate than either of those I have mentioned. The inhabitants of that region are of a swarthy colour, with curly hair and slender bodies, and the trees of their country do not grow to any height, and day does not exceed fourteen hours, and neither is it ever less than ten hours in that region.

The nature of the fourth zone:

The climate of this region is more temperate than that of the other regions I have mentioned, because they have no excessive cold or heat, and they abound and are enriched by the variety of exotic trees and many fruits of the earth, and the inhabitants of the first and second regions can dwell in it easily and without danger. The inhabitants of that region are of a yellow colour, between white and swarthy, they are intellectual and refined, with good memories and much wisdom; and in this country the greatest number of people of great knowledge and wisdom, generosity and physical strength have been. Also the water of that country tastes better than that of the others. Day never exceed fifteen hours, nor is less than nine hours, in that region.

The nature of the fifth zone:

Its heat is less, and its cold greater than that of the preceding region, and yet their trees are more numerous, and the fruit of their fields more excellent. The inhabitants of that country have medium-sized bodies their complexion is neutral,209 nearer to white than to swarthy, their wisdom is less and their life shorter, and they are wealthier than the people of the preceding climate. And daylight extends to sixteen hours, and diminishes to eight hours in that region.


The nature of the sixth zone:

Its heat is less and its cold greater than that of the preceding regions, and the produce of its trees and fields is less than that of the preceding regions, on account of its coldness, and great is the snow and rain, and many are the clouds, wells, rivers, hills and mountains of that region. The inhabitants of that region have weak bodies, are of fair complexion, with smooth hair, while they are savage and uncouth. The longest day of that region is of seventeen hours duration, and the shortest day eight and a half210.

The nature of the seventh zone is, lack of heat and excess of cold.

The inhabitants of that region are unintelligent and uncouth, with weak minds and brutish memories, and weak bodies, and smooth, fair, yellow hair; and if the inhabitants of this region went to the first or second region, or if the inhabitants of those regions came to this one, both of them would die on account of the change of climate.

Therefore, the fourth region is the most temperate, and is the best of them, all things considered, for the mildness of the heavens nurtures that region beyond all. The longest day in that region i.e., the seventh is eighteen hours, and the shortest six211.