But if a single individual, by observations continued unbroken for entire decenniums, has thus revealed to us the most important fact hitherto known relating to the sun, there are other questions not less important which can only find their solution in the careful observation of a rarely-occurring interval of perhaps one or two minutes. The splendor of the sun is so amazingly great, as to preclude us entirely from perceiving any object in his immediate proximity unless projected before his disk as a darkening object. At ten, or fifteen degrees even from the sun, when this luminary is above the horizon, all the fixed stars vanish from the most powerful telescopes. We are therefore in utter ignorance whether the space between him and Mercury is occupied or not by some other denizen of the planetary system. To enable us to explore the sun’s immediate proximity, we require a body that shall exclude his rays from our atmosphere, and yet leave the space round the sun open to our view. Such an object can of course be neither a cloud nor any terrestrial object, natural or artificial, since parts of the atmosphere will exist behind it which will be impinged on by the sun’s rays. Only during a total eclipse can these conditions be fulfilled, and even then but for a very brief interval, which may still be lost to the observer through unfavorable weather or from too low a position of the sun. Notwithstanding that this rare and precarious opportunity is the only possible one we possess of becoming better acquainted with the physical nature of the great luminary of day, astronomers never availed themselves of it for any other purpose than the admeasurement of the earth, which might have been done as well, if not better, during any planetary eclipse. This error or indifference, whichever it may have been, can not, however, be laid to the charge of our living astronomers. The 8th of July, 1842—the day on which the last total eclipse of the sun took place—witnessed the most distinguished of these assembled for the purpose of making, for the first time, observations calculated to afford us some insight into this greatest mystery of the celestial world. This eclipse was total on a zone which traversed the north of Spain, the south of France, the region of the Alps and Styria, and a portion of Austria, Central Russia and Siberia, terminating in China; so that the observatories of Marseilles, Milan, Venice, Padua, Vienna, and Ofen, all supplied with excellent telescopes, and in full activity, came within its range; while many astronomers, at whose observatories the eclipse was not visible, set out for places situated within the zone just described. Thus Arago and two of his colleagues repaired to Perpignan, Airy to Turin, Schumacker to Vienna, Struve and Sehidloffsky to Lipezk, and Stubendorff to Koerakow. Most of them were favored by the weather. Let us now see what the combined endeavors of these practiced and well-furnished observers have made us