planation of the apparently polar forces at play in the evolution of the comet. Bessel's theory is, that at a great distance all the particles have a polarity opposite to that of the sun, but that on a near approach the comet itself, as a distinc unit, is polarised, so as to emit streams of luminous matter. The repelling of the luminous matter is not satisfactorily accounted for. Another theory has recently been started, which has, for the tim'e, put all others in abeyance, and is in process of being tested by the French savans. We allude to the hypothesis of M. Faye, which is, that there is a repelling force radiated from the sun, as well as the attractive force of gravitation, and that this is only a single case of a universal law of matter. He maintains that every incandescent body exercises this repulsion, but that it is so feeble, that it can be detected only in the case of matter of such extreme tenuity as that of comets. He supposes that the force emanates only from the surface of the sun, and not, like gravitation, from its mass. With this simple assumption, he endeavours to explain the formation and all the phenomena of comets. The envelopes are produced by the expansive power of the sun's heat, balanced by this special repelling power. The shortening of the period of the comet of Encke, is also explained by the same means. He has agreed to submit the law to the test of experiment. It was objected, that if the incandescent surface of the sun repelled the rarefied matter of comets, the
