He has satisfied himself that the corona is not the atmosphere of either the sun or moon. He holds that it is not an objective substance at all, but merely an affection of light, due to the edge of the moon. When light passes the edge of opaque bodies, it is diffracted and bent into the shadow. Foucault holds that the corona is merely the diffracted light of the sun. The radial beams of light seen in the corona, he ascribes to prominences in the contour of the moon. This conclusion cannot be admitted. There is, on other grounds, every probability that there is an atmosphere in winch the various solar strata float, and we would have reason to expect that this atmosphere would be rendered visible in a total eclipse. Father Secchi declares, that he saw the corona for a few seconds after the disc of the sun appeared; and such a phenomenon is incompatible with the theory of diffraction. None of the observations have given any countenance to the idea, that the corona is the atmosphere of the moon. Mr Airey holds that the phenomenon would receive a satisfactory explanation dn the supposition that the earth's atmosphere extended to the moon. The corona, in that case, would be only a portion of the earth's atmosphere illuminated by the sun. The result of the observations of the late eclipse amounts to this, that the red prominences have been proved, beyond all doubt, to belong to the sun, and that they are mere elevations of a stratum of the same matter enveloping the whole solar sphere. The photographic observa-
