plane or concave surface, _heat_ will be reflected. If snow or ice be similarly placed, _cold_ will be reflected. If light, ordinary or coloured, be presented, the _same_ will be reflected. If sound of a given pitch be produced, the same pitch will be reflected. If the note A be sounded upon a musical instrument, a reflector would not return the note B or C, but the _same note_, altered only in degree or intensity, but not in “pitch.” A reflector receiving a red light would not return a blue or yellow light. A reflector collecting the cold from a mass of ice, would not throw off heat; nor the contrary. Nor could the Moon, if a reflector, radiate or throw down upon the Earth any other light than such as she receives from the Sun. No difference could exist in the quality or character of the light, and it could differ in no respect but the quantity or intensity. The light of the Sun and of the Moon are different in their general appearance--in the colour and action upon the eye. The Sun’s light is drying and preservative, or antiseptic. The Moon’s light is damp and putrefactive. The Sun’s rays will put out a common fire; the Moon’s light will increase the combustion. The light of the Sun falling upon certain chemical substances, produces a change of colour, as in photographic and other processes. The light of the Moon fails to produce the same effect. Dr. Lardner, at page 121 of his excellent work, “The Museum of Science,” says--“The most striking instance of the effect of certain rays of solar light in blackening a light-colored substance, is afforded by chloride of silver, which is a white substance, but which immediately becomes black when acted upon by the rays near the violet extremity of the spectrum. This substance, however, highly susceptible as it is of having its colour affected by light, is, nevertheless, found not to be changed in any sensible degree when exposed to the light of the Moon, even when that light is condensed by the most powerful burning lenses.”