The art of Photography is one of the most pleasing and curious results of chemical philosophy, and certainly not one of the least useful. Those who have beheld on the field of a camera obscura the minutely perfect reflection of a landscape, with its rivulet, its well-clad trees, and its animated groups, must have regretted that it was but a shadow doomed to exist only for a moment, while the light shone or the instrument remained stationary. Photography, however, enables us to render permanent the objects thus reflected. To accomplish this, no tedious or troublesome process is necessary; unlike the creations of the artist's pencil, the pictures thus produced are not the result of long and tiring manipulation. In a moment our work is over-our desires accomplished. In order that the reader, who may have hitherto paid but little attention to such subjects, may form some idea of the mode in which light acts so as to produce pictures upon prepared paper or metallic plates, rendered sensitive to its influence, we shall for a short time refer to certain well-known effects of light on plants, animals, and chemical compounds. W. Raleigh Baxter, 1842