I am rather surprised, Mrs. B., that you should have said so much of the light emitted by phosphorescent bodies without taking any notice of that which is produced by burning bodies.
MRS. B.
The light emitted by the latter is so intimately connected with the chemical history of combustion, that I must defer all explanation of it till we come to the examination of that process, which is one of the most interesting in chemical science.
Light is an agent capable of producing various chemical changes. It is essential to the welfare both of the animal and vegetable kingdoms; for men and plants grow pale and sickly if deprived of its salutary influence. It is likewise remarkable for its property of destroying colour, which renders it of great consequence in the process of bleaching.
EMILY.
Is it not singular that light, which in studying optics we were taught to consider as the source and origin of colours, should have also the power of destroying them?
CAROLINE.
It is a fact, however, that we every day experience; you know how it fades the colours of linens and silks.
EMILY.
Certainly. And I recollect that endive is made to grow white instead of green, by being covered up so as to exclude the light. But by what means does light produce these effects?