BİRİNCİ FEN · ÜÇÜNCÜ BÂB · İKİNCİ FASIL · Birinci Madde
Article One
It describes the place (location), nature, distance, circumference, and movements of the aerial sphere.
O esteemed one! It must be known that philosophers and astronomers agree as follows: The second of the four aforementioned elements [63/a] is air, a simple body enclosed by two parallel surfaces, a spherical substance. Its convex surface is at the same level and touches the concave surface of the fire sphere. Its concave surface touches the surfaces of the water sphere and the earth. Due to waves and the ruggedness of mountains, the surface of the air is not smooth. Therefore, the natural place of air is beneath the fire sphere and above the water sphere. In this state, it remains at rest in its place and moves with its own specific movements. When it is at rest, it is called air; when it moves, it is called wind.
The element of air is subtle, transparent, and colorless. Its inherent qualities are warmth, moisture, and a tendency to rise, by which it differs from the other three elements. Air is prone to transforming into various formations and compositions, changing shape over time. For even when at rest, it can transform into the other three elements.
Space observers, mathematicians, and geometricians agree as follows: The total distance of the aerial sphere, in terms of thickness and depth, is approximately fifteen thousand two hundred twenty-six (15,026) parasangs, and it is accepted to consist of three layers. The uppermost layer, due to its proximity to the fire sphere, is warm and rotates from east to west, seemingly accompanying the moon’s movement under its influence. The upper part of this layer experiences rapid motion due to the effect of heat. The lower layers of the aerial sphere, as they move away from the fire, reduce their heat and remain in their natural state. The rotational movement of the aerial sphere is slow, and its lower side remains at rest. The depth and thickness of this layer have been determined to be ten thousand (10,000) parasangs, and it is considered the second layer relative to the fire sphere. Smoke rising from below separates here, so it is called the “smoke layer” (tabaka-i duhâniye), and many of its secrets have been discovered.