Having thus endeavored to explain what electricity is, and the laws which govern the occlusion of static caloric, and the development of dynamic caloric (electricity), in conclusion I call the attention of the inventors of the age to the great need of a process for oxidizing coal or oil at a low degree, within an insulated vessel. With such an invention electricity would be obtained at such a low cost that it would be used exclusively to light and heat our houses, to smelt, refine, and manipulate our metals, to propel our cars, wagons, carriages, and ships, cook our food, and drive all machinery requiring motive power. * * * * * ELECTRIC LIGHT APPARATUS FOR PHOTOGRAPHIC PURPOSES. By A.J. JARMAN. For some time past it has been the desire of many photographers to have at hand a ready means of producing a powerful and highly actinic artificial light, suitable for the production of negatives, and easily controllable. Several forms of apparatus have been designed, and I believe have been, to a certain extent, employed successfully in portraiture. But it has been well known for many years that the electric light was just the light that would answer the photographer's requirements, owing to its possessing great actinic power; but the cost of its production was too great for general adoption; indeed, such might be said of it now as far as dynamo-electric machines and steam or gas motors are concerned, for the majority of photographers. It is true that several influential photographers have already adopted the use of the electric light for portraiture, but the primary cost of the apparatus employed by these firms is far beyond the reach of most portraitists. The apparatus about to be described is one that has been carefully worked out to meet the wants of the photographer in almost every particular; in fact, with this apparatus, portraits can, and have been, produced in an ordinary sitting room, as good and as perfect as if taken in a well-lighted studio. [Illustration: FIG. 1.] The generator of the electric current consists of a series of voltaic elements of zinc and carbon--forty-eight in number--these elements being made up of ninety-six zinc plates and forty-eight carbon plates; thus the generator consists of forty-eight voltaic elements arranged in rows of twelve; they are all carefully screwed upon suitable bars of wood, and these bars are joined by other cross bars, which bind the whole in a compact form; the battery being suitably connected so as to produce a current of very high electro-motive force, and so arranged over their exciting trough that the plates can be raised or lowered at will, as seen in Fig. 1, which will explain itself almost at first sight.