Because the cloth absorbs heat from the rays of the sun, and, therefore, melts the snow beneath it.
Why does not white muslin, when spread on the snow, hasten its melting?
Because the white muslin reflects the heat from the rays of the sun, so that but little of it enters the snow.
Does the snow receive much heat from the sun?
Snow is a good reflector, and throws back most of the heat from the sun.
What causes the snow to melt?
The heat it receives from touching the earth, causes the most of it to melt.
Why does snow melt first on dark earth?
Because dark earth is a good radiator, and gives off much heat to the snow.
Why does snow remain longest on light-colored earth?