M. F. W. G. Struve gives as the splendid result of the united studies of MM. Argelander, O. Struve, and Peters, grounded on observations made at the three Russian observatories of Dorpat, Abo, and Pulkowa, “that the velocity of the motion of the solar system in space is such that the sun, with all the bodies which depend upon it, advances annually towards the constellation Hercules[17] 1·623 times the radius of the earth’s orbit, or 33,550,000 geographical miles. The possible error of this last number amounts to 1,733,000 geographical miles, or to a _seventh_ of the whole value. We may, then, wager 400,000 to 1 that the sun has a proper progressive motion, and 1 to 1 that it is comprised between the limits of thirty-eight and twenty-nine millions of geographical miles.” That is, taking 95,000,000 of English miles as the mean radius of the Earth’s orbit, we have 95 × 1·623 = 154·185 millions of miles; and consequently, English Miles. The velocity of the Solar System 154,185,000 in the year. ” ” 422,424 in a day. ” ” 17,601 in an hour. ” ” 293 in a minute. ” ” 57 in a second. The Sun and all his planets, primary and secondary, are therefore now in rapid motion round an invisible focus. To that now dark and mysterious centre, from which no ray, however feeble, shines, we may in another age point our telescopes, detecting perchance the great luminary which controls our system and bounds its path: into that vast orbit man, during the whole cycle of his race, may never be allowed to round.--_North-British Review_, No. 16. NATURE OF THE SUN. M. Arago has found, by experiments with the polariscope, that the light of gaseous bodies is natural light when it issues from the burning surface; although this circumstance does not prevent its subsequent complete polarisation, if subjected to suitable reflections or refractions. Hence we obtain _a most simple method of discovering the nature of the sun_ at a distance of forty millions of leagues. For if the light emanating from the margin of the sun, and radiating from the solar substance _at an acute angle_, reach us without having experienced any sensible reflections or refractions in its passage to the earth, and if it offer traces of polarisation, the sun must be _a solid or a liquid body_. But if, on the contrary, the light emanating from the sun’s margin give no indications of polarisation, the _incandescent_ portion of the sun must be _gaseous_. It is by means of such a methodical sequence of observations that we may acquire exact ideas regarding the physical constitution of the sun.--_Note to Humboldt’s Cosmos_, vol. iii. STRUCTURE OF THE LUMINOUS DISC OF THE SUN.