diathermanous

Water, on the contrary, is not diathermanous, and it is heated by sunshine directly.

However, water needs much more time to heating up than land does and atmosphere air is not heated by solar rays because it is diathermanous.

A diathermanous fluid is thus "permeable" by heat.)

Atmospheric air is diathermanous; therefore, air it is not heated by sunshine, but by long wave heat reflected by soil and water on the Earth surface.

"Those who, like myself, have been taught to regard transparent gases as almost perfectly diathermanous (transparent to heat), will probably share the astonishment with which I witnessed the foregoing effects," he wrote.