Of the total eclipses which have of late years been systematically observed, that of July 18, 1860, is by far the most interesting and important: it owes its interest to the agreeable circumstances connected with it, hereafter to be more fully spoken of, and its importance, to the very extensive and refined observations which were made by so many astronomers in America, Europe, and Africa.

Our limits wholly forbid our entering into any very lengthened statement: we shall therefore select from the published accounts of the observations, such portions as we deem most fitted to be placed on record in a work like the present, prefacing them by a brief epitome of the general circumstances attending “ the Himalaya Expedition.”

On Nov. 15, 1859, the Astronomer Royal, in an interview with the Duke of Somerset, First Lord of the Admiralty, drew his Grace's attention to the then approaching eclipse, at the same time suggesting the desirability of a ship being appropriated for the conveyance of observers to and from the coast of Spain. After the request was duly considered, Her Majesty's Government volunteered to place at the disposal of the Astronomer Royal and his friends, H.M.S. “ Himalaya”; the offer was of course gratefully accepted, and in due course of time the expedition set forth.

This planet was discovered by Sir W. Herschel on March 13, 1781, whilst he was engaged in scrutinising some small stars in Gemini. He observed one of them which seemed to have a more sensible diameter than the others, and to be less luminous. The application of high magnifying powers rendered these peculiarities more perceptible: he therefore made some very careful observations, and found that it was moving at the rate of 2¼″ per hour. He then announced to the Royal Society the discovery of a new comet, so little was a planet expected. Maskelyne found it, and soon suspected its true nature. On proper inquiries being made, it was found that Flamsteed had seen it 3 times, Mayer, once, and Le Monnier, 11 times previously to the epoch of Herschel's discovery; all of whom had been ignorant of its real nature.

A brisk discussion took place on the name the new planet was to have. Herschel himself desired to call it the Georgium Sidus in compliment to his friend and patron, our most excellent Sovereign King George III.; some of the foreign astronomers, amongst whom was Laplace, insisted that it ought to bear the name of its discoverer; Bode proposed Uranus as the mythological father of Saturn; and this name finally triumphed, though for a long course of years it was frequently known as the Georgian Planet.

The class of phenomena we are about to describe are those produced by the interposition of celestial objects; for we know well that inasmuch as many of the heavenly bodies are constantly in motion, it follows that the direction of lines drawn from one to another will vary from time to time; and it must occasionally happen that three will come into the same line. “ When one of the extremes of the series of 3 bodies, which thus assume a common direction, is the Sun, the intermediate body deprives the other body, either wholly or partially, of the light which it habitually receives. ”When one of the extremes is the Earth, the intermediate body intercepts, wholly or partially, the other extreme body from the view of observers situate at places on the Earth which are in the common line of direction, and the intermediate body is seen to pass over the other extreme body, as it enters upon or leaves the common line of direction, and the intermediate body is seen to pass over the other extreme body, as it enters upon or leaves the common line of direction. The phenomena resulting from such contingencies of position and direction are variously denominated ‘Eclipses’ ‘Transits’ and ‘Occultations’ according to the relative apparent magnitudes of the interposing and obscured bodies, and according to the circumstances which attend them.“ We shall proceed to consider the several phenomena in detail, beginning with Eclipses.

Variation in the Obliquity of the Ecliptic. — Although it is sufficiently near for all general purposes to consider the inclination of the plane of the ecliptic as invariable; yet this is not strictly the case, inasmuch as it is subject to a small but appreciable change of about 48″ per century. This phenomenon has long been known to astronomers, on account of the increase it gives rise to, in the latitude of all stars in some situations, and corresponding decrease in the opposite regions. Its effect at the present time is to diminish the inclination of the two planes of the equator and the ecliptic to each other; but this dimimition will not go on beyond certain very moderate limits, after which it will again increase, and thus oscillate backwards and forwards through an arc of 1 ° 21 ′: the time occupied in one oscillation being about 10,000 years. One effect of this variation of the plane of the ecliptic—that which causes its nodes on a fixed plane to change—is associated with the phenomena of the precession of the equinoxes, and undistinguishable from it, except in theory.

Precession.—The precession of the equinoxes is a slow but continual shifting of the equinoctial points from East to West.

The early origin of the telescope, like that of most other important inventions, is lost in obscurity, and it is now impossible to determine who was the first maker. It is certain that some time prior to the end of the 13th century lenses were in common use for assisting in procuring distinctness of vision. A certain Vitello, a native of Poland, seems to have done something in this line; and Eoger Bacon, in one of his works, employs expressions which show that even in his time (he died in 1292), spectacles were known.

Seeing that this was the case, it is almost certain that some combination of 2 or more lenses must have been made in the interval which elapsed between Bacon's time and the commencement of the 17th century, when telescopes are usually considered to have been invented. Dr. Dee mentions that though some skill is required to ascertain the strength of an enemy's force, yet that the commander of an army might wonderfully help himself by the aid of “perspective glasses,” a phrase which must refer to some kind of optical instrument then in use

One of the most important total eclipses of the Sun. that has occurred within the last few years was that of July 28, 1851. Though not visible in England, it was seen to great advantage in Sweden, to which country astronomers flocked in great numbers. From the numerous observations that were made, and subsequently published, we select some extracts which will doubtless interest the reader. The following remarks are from the pen of Mr. G. B. Airy, the Astronomer Royal, who observed it at Göttenberg: —