Colored Flames.
A variety of rays of light are exhibited by colored flames, which are not to be seen in white light. Thus pure hydrogen gas will burn with a blue flame, in which many of the rays of light are wanting.
The flame of an oil lamp contains most of the rays which are wanting in the sunlight. Alcohol mixed with water, when heated or burned, affords a flame with no other rays but yellow. The following salts, if finely powdered, and introduced into the exterior flame of a candle, or into the wick of a spirit lamp, will communicate to the flame their peculiar colors:
| Chloride of Soda (common salt) | Yellow. |
| “ of Potash | Pale violet. |
| “ of Lime | Brick red. |
| “ of Strontia | Bright crimson. |
| “ of Lithia | Red. |
| “ of Baryta | Apple green. |
| “ of Copper | Bluish green. |
| Borax | Yellow. |
Or either of the above salts may be mixed with spirit of wine, as directed, for Red Fire.