MESSES. EDITORS.—I have lately noticed an article going the round of the papers, relative to a new theory, which I think is open to objections. It is that which contends for the existence of an open polar sea, and a warmer climate in those regions than we have heretofore been taught to imagine. The advocates of this hypothesis give a coloring to their conclusions by citing certain phenome na which have been observed in high northern latitudes, such as the flight of large flocks ol birds to the north, currents setting north- ward, and so on, but they chiefly rely upon the theory of the igneous origin of our planet to prove their point. For instance, they say since the earth's diameter from pole to pole'Js shorter than its equatorial diameter, the distance of$he surface at the poles from the centre being less, a proportional increase of temperature must follow, for if we descend below the surface at any point, even for a moderate distance, a considerable change is lelfc. Some, I believe, have gone so far as to suppose a concavity at its poles, giving the earth somewhat the shape of an apple, whence, according to their reasoning, an almost tropical climate would be found if we could only pass the intermediate barrier of ice, and arrive there. Now, if we admit the only theory irom which these hypotheses can receive the slightest support (and it is one which has received the sanction of some of the greatest scientific men of our own time.) I think it can be shown that they are entirely fallacious. The main point of this theory is, that our planet was originally a molten, liquid mass, and that by the radiation ot its surface heat into spacei the present crust was formed. Now, we can see no reason why the present crust should be thinner at the poles than at the equator. On the contrary it would be thicker, since, at the equator, the vertical sun's rays would always help towards maintaining the original heat, while at the poles the cooling down process could go on with little or nothing to counteract it. Hence we have two reasons why the cold should be very intense at the poles:mdash;first, the absence of the sun's rays, and second, the greater distance of the surface from the intense heat. As for the concavity at the poles, no reason can be assigned why it should exist there any more than at any other points on the surface. A liquid, revolving mass will always assume the form of an oblate spheroid, unless, indeed, the cen-tritugal force is great enough to cause it to take the form of a ring, and even then, nothing but a remarkable uniformity of density will prevent its separating into parts. The figure of tha earth has been determined with great exactness by mathematicians, and the amount by which it varies from an exact sphere is such as we would be led to infer from its known density, size, and rate of revolution. Yours, amp;c, H. H. BATES. Geneva, Jan. 8, 1853. [Our correspondent effectually disposes of the igneous theory affecting the fluidity of the seas at the poles; this theory, as advanced for an open polar sea, we have considered of no value; butthe facts ofcurrents, flocks of birds, and passages of northern whales, from the Atlantic to the Pacific Ocean by the Northern Seas, are evidences of an open sea at the north not to be overlooked. It is our opinion however,that there is no fixed open arctic sea.