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universe is replenished. This nebula is situated in right ascension 19h 52', north declination 22° 16'; in the breast of Anser et Vulpecula, about midway between Albireo in the Swan, and the principal stars of the Dolphin, about three or four degrees north of Sagitta, a star of the fourth magnitude. Fig. 48 is likewise a very remarkable object. It consists of a bright round nucleus or central part, surrounded at a great distance by a nebulous ring. This ring appears split through nearly the greater part of its circumference, the two portions of which being separated at about an angle of 45°. This nebula lies near the remotest boundaries to which our telescopes can carry us. It has never been resolved into stars by the highest powers that have yet been applied; but there is little doubt that it is a grand scheme of sidereal systems, perhaps exceeding our Milky Way in number and magnificence. It is, indeed, supposed to bear a more striking resemblance to the system of stars in which the sun is placed than any other object which has yet been discovered in the heavens, as may be perceived by turning to figure 39 (p. 156), which represents Sir W. Herschel's scheme of the Milky Way; and hence Sir John Herschel describes it as "a brother system, bearing a real physical resemblance and strong analogy of structure to our own." This object, dim and distant as it may appear through our telescopes, and utterly invisible as it is to the unassisted eye, may be considered as a kind of universe in itself, ten thousand times more grand and extensive than the whole creation was supposed to be in the infancy of astronomy. Like the preceding nebula, it shows us what singular varieties of structure are to be found in the systems which compose the universe, and, at the same time, it exhibits a certain resemblance to another system of which we form a part; and perhaps something similar, though not precisely of the same form and arrangement, may be found in other parts of the sidereal heavens. This phenomenon is situated near the back of Asterion, about five degrees south by west of Benetnasch, the last star in the tail of the Great Bear; between which star and the nebula there is a small star of the fifth magnitude, nearer to the nebula than to Benetnasch. Its right ascension is 13h 22', and north declination 46° 14'. Figures 49, 50, 52, 53, 54, 55, 56, 57, and 58, represent some specimens of nebulous stars, or of nebulæ connected with very small stars.

Fig. 49 shows a nebulosity, or something like a nebulous stream, extending from one small star to another, as if there was a communication between them. The next three figures are representations of similar phenomena. In fig. 52, the nebulous substance appears much broader than in the others, though this may possibly be owing to the nebula in its greatest extent being presented to our line of vision.

Figs. 54, 55, 56, are very small stars, with faint and small nebula attached to them in the shape of a puff. Fig. 57 is a small star, with a small, faint, fan-shaped nebulosity joined to it. Fig. 58 represents two considerable stars involved in a very faint nebulosity of three or four minutes in extent. What this nebulous substance in reality is, or what connexion it may have with the stars which appear in its vicinity, it is difficult to conjecture. It is a species of nebula which does not appear to be resolved into stars, and therefore may be regarded as a distinct luminous substance, diffused throughout the different regions of the universe, subserving some important designs in the physical economy of creation of which we are ignorant. Specimens of some of these phenomena will be found in the following situations: 1. Right ascension 20h 56', north declination 11° 24'; a little to the east of the cluster of stars called the Dolphin. 2. Right ascension 8h 46', north declination 54° 25'; about seven degrees northwest of the star Theta of the Great Bear. 3. Right ascension 12h 51', north declination 35° 47'; about four degrees south of the star Cor Caroli, the principal star in the Greyhounds. 4. Right ascension 6h 30', north declination 8° 53′; which is in the head of Monoceros, or the Unicorn, about eleven degrees east of Betelguese, in the right shoulder of Orion, and about seven degrees due south of y Gemini, which is in the left foot of one of the Twins,

Figs. 59 to 65 represent a few specimens of objects which come under the denomination of extensive diffusive nebulosities. These phenomena were very little noticed till lately, and can only be perceived by telescopes of large aperture, which collect a great quantity of light. In adverting to one of these objects, Sir W. Herschel describes it as follows: "Extreme faint branching nebulosity; its whitishness is entirely of the milky kind, and it is brighter in three or four places than the rest; the stars of the Milky Way are scattered over it in the same manner as over the rest of the heavens.