Those who have offered other explanations of these vast ring-formed mountain ranges, have been no more happy in their conjectures. M. Rozet, who communicated a paper on selenology to the French Academy in 1846, put forth the following theory. He argued that during the formation of the solid scoriaceous pelicules of the moon, circular or tourbillonic movements were set up; and these, by throwing the scoria from the centre to the circumference, caused an accumulation thereof at the limit of the circulation. He considered that this phenomenon continued during the whole process of solidification, but that the amplitude of the whirlpool diminished with the decreasing fluidity of the surface material. Further, he suggested that when many vortices were formed, and the distances of their centres, taken two and two, were less than the sums of their radii, there resulted closed spaces terminated by arcs of circles; and when for any two centres the distance was greater than the sum of the radii of action, two separate and complete rings were formed. We have only to remark on this, that we are at a loss to account for the origination of such vorticose movements, and M. Rozet is silent on the point. If the great circles are to be referred to an original sea of molten matter, it appears to us more feasible to consider that wherever we see one of them there has been, at the centre of the ring, a great outflow of lava that has flooded the surrounding surface. Then, if from any cause, and it is not difficult to assign one, the outflow became intermittent, or spasmodic, or subject to sudden impulses, concentric waves would be propagated over the pool and would throw up the scoria or the solidifying lava in a circular bank at the limit of the fluid area.