Abstract
The heat absorption of clothing materials depends on their property such as hue, reflection coefficients, etc. We made experiments concerning the heat absorption of clothes under the direct rays of the sun. In the first place, the spectral distribution of direct solar radiation reacting the materials with different heat absorption was obtained according to Lambert's law. Further, the relation between the quantity of incident heat, the altitude of the sun, and the heat absorption was made clear.
The results obtained are :
1. The heat quantity absorbed by the materials in affected by the reflection coefficients of the materials.
2. The heat quantity absorbed by the materials changes considerably with the altitude of the sun.
3. The temperature variation of the material due to the incident rays is white<green<black, the temperature differences being considerable.
