increased or diminished; and this process must continue, without further loss or change, indefinitely into the future. Whatever the sun may gain by increment of meteoric masses may pass for what it is worth, but the gradual contraction of his volume cannot proceed while his present temperature is maintained by the passage of such currents,--that is to say, his light and heat will remain constant, and also his mass and volume, so long as the electric currents which pass from the planets to the sun and the constitution of space which surrounds the sun and planets themselves remain constant. It now remains to consider how such enormous currents of electricity can be generated and maintained. We know, of course, that chemical changes cannot operate to produce them. They must be derived from something contained in or diffused through interplanetary space, and the planets themselves must be the means by which such currents of electricity are brought into effective operation. On our own earth we have many kinds of mechanically-constructed electrical apparatus which generate electricity, to use a popular expression, or which, more properly, separate the opposite potentials from an unstable electrical tension or equilibrium of the matter of space. These machines practically take positive electricity from the mutually-balanced electric potentials of which the earth and its surrounding gaseous envelope are the vast common storehouse, in such manner that the positive electricity thus drawn out from and again passing into the common storehouse shall, during such transit, be compelled to pass through channels which will cause it to do work, at the expense of its potential or pressure, during its passage, or in which electricity is raised in its electro-motive force from a lower to a higher potential or pressure, just as the pressure of water is increased when delivered from a greater or a still greater height, or steam, when confined in space under higher and still higher temperatures. But none of these machines actually generate electricity ab initio; they merely put into effective operation the pre-existing force. The mass of the earth is of irregularly negative polarity, the air above is positive, and as we ascend, the potential, or voltage, or pressure increases at a nearly uniform rate of from twenty to forty volts for each foot. The earth is thus surrounded by an electrosphere as well as an atmosphere, and the two are not coincident, for while the pressure of the atmosphere diminishes as we ascend, that of the electrosphere increases. The moon, too, and each planet must have its electrosphere, and around the sun's core we can see the solar electrosphere in its visible glory. Thus, all our planets rotate upon their axes and revolve around the sun, each surrounded by an enormous electrosphere, just as an electrical induction machine is surrounded, when in operation, with an electrosphere of its own, and which,