Materials and a system of construction such as those we have described could only result, in a close style of architecture, in a style in which the voids bore but a very small proportion to the solids. And such a style was well suited to the climate. In the long and burning summers of Mesopotamia the inhabitants freely exchanged light for coolness. With few and narrow openings and thick walls the temperature of their dwellings could be kept far lower than that of the torrid atmosphere without.[158] Thus we find in the Ninevite palaces outer walls of from fifteen to five-and-twenty feet in thickness. It would have been very difficult to contrive windows through such masses as that, and they would when made have given but a feeble light. The difficulty was frankly met by discarding the use of any openings but the doors and skylights cut in the roofs. The window proper was almost unknown. We can hardly point to an instance of its use, either among Assyrian or Chaldaean remains, or in the representations of them in the bas-reliefs. Here and there we find openings in the upper stories of towers, but they are loop-holes rather than windows (Fig. 38).[159] [Illustration: FIG. 38.--A Fortress. From Layard.] At first we are inclined to pity kings shut up within such blind walls as these. But we must not be betrayed into believing that they took no measures to enjoy the evening breeze, or to cast their eyes over the broad plains at their feet, over the cities that lay under the shadows of the lofty mounds upon which their palaces were built. At certain times of the year and day they would retire within the shelter of their thickest walls and roofs; just as at the present moment the inhabitants of Mossoul, Bassorah, and Bagdad, take refuge within their _serdabs_ as soon as the sun is a little high in the heavens, and stay there until the approach of evening.[160]