In fabulous history it is said that in the Pleiades the star Merope, one of the Atlantides, appears more dim and obscure than the rest, or is altogether extinguished, because, as the poets fancy, she married a mortal, while her sisters married some of the gods or their descendants. Dr. Long, however, declares that he himself had more than once seen seven stars in this group; and a learned astronomical friend assured him that he had seen eight stars among the Pleiades, where common eyes can discover but six; and Kepler says of his tutor Mæstlinus, that "he could reckon fourteen stars in the Pleiades without any glasses." This difference in the number seen by different persons in this group is obviously owing to the different degrees of acuteness of vision possessed by the respective individuals. However small the number perceived by the naked eye, the telescope shows them to be a pretty numerous assemblage. Dr. Hook, formerly professor of geometry in Gresham College, informs us that, directing his twelve-feet telescope (which could magnify only about seventy times) to the Pleiades, he did in that small compass count seventy-eight stars; and making use of longer and more perfect telescopes, he discovered a great many more of different magnitudes.

The ingenious Mr. Mitchell, more than fifty years ago, started the idea of the stars being formed into groups or systems which are entirely detached from one another, and have no immediate connexion. In reference to the Pleiades, he conducted his reasoning as follows: "The Pleiades are composed of six remarkable stars, which are placed in the midst of a number of others that are all between the third and sixth magnitudes; and comparing this number six with the whole number visible in the heavens to the naked eye, he calculated, by the doctrine of chances, that among all this number, if they had been dispersed arbitrarily through the celestial vault, it was about five hundred millions to one that six of them should be placed together in so small a space. It is therefore so many chances to one that this distribution was the result of design, or that there is a reason or cause for such an assemblage."

The constellation called Coma Berenices is another group, more diffused than the Pleiades, which consists chiefly of small stars which can scarcely be distinguished in the presence of the moon. This beautiful cluster lies about five degrees east

of the equinoctial colure, and midway between the star Cor Caroli on the northeast, and Denebola, in the Lion's tail, on the southwest, If a straight line be drawn from Benetnasch -the star at the extremity of the tail of the Great Bearthrough Cor Caroli, and produced to Denebola, it will pass through this cluster. It may also be distinguished as situated about twenty-six degrees west by north from the bright star Arcturus. The confused lustre of this assemblage of small stars bears a certain resemblance to that of the Milky Way, and, besides the stars of which it is chiefly composed, it contains a number of nebula. Sir W. Herschel supposes that the stratum of nebulæ in this quarter runs out a very considerable way, and that it may even make the circuit of the heavens, though not in one of the great circles of the sphere. He also supposes that the situation of the stratum is nearly at right angles with the great sidereal stratum in which the sun is placed; that the Coma itself is one of the clusters in it; and that it is on account of its nearness that it appears to be so scattered. He apprehends that the direction of it towards the north lies probably, with some windings, through the Great Bear onward to Cassiopeia, thence through the girdle of Andromeda and the Northern Fish, proceeding towards Cetus; while towards the south it passes through the Virgin, probably on to the tail of Hydra and Centaurus.

Another group, somewhat similar, but less definite, is found in the constellation of Cancer; it is called Præsepe, or the Bee Hive, and is a nebulous cluster of very minute stars, not separately distinguishable by the naked eye. A telescope of very moderate power, however, easily revolves it into small stars. It is sufficiently luminous to be seen as a nebulous speck by the unassisted eye, and is somewhat like the nucleus of a comet, for which it has frequently been mistaken by ordinary observers. It is situated in a triangular position with regard to Castor and Procyon, or the Little Dog. A line drawn from Procyon in a northeasterly direction meets with Præsepe at the distance of twenty degrees. This line, drawn in a northwesterly direction from Præsepe, meets Castor at the same distance. These lines form nearly a right angle, the angular point being in Præsepe. It may otherwise be discovered by means of two stars of the fourth magnitude lying one on either side of it at the distance of about two degrees. It may likewise be found by conceiving a line drawn through

Castor and Pollux to the southeast, and continued about fifteen degrees, or three times the distance between Castor and Pollux. This cluster, Sir W. Herschel thinks, belongs to a certain nebulous stratum so placed as to lie nearest us. This stratum runs from & Cancri towards the south, over the 67th nebula of the Connoissance des Temps, which is a very beautiful and much compressed cluster of stars, easily to be seen by any good telescope, and in which he has observed about 200 stars at once in the field of view of his great reflector, with a power of 157. This cluster appearing so plainly with any good common telescope, and being so near to the one which may be seen with the naked eye, denotes it to be probably the next in distance to that within the quartile formed by 780. From the 57th nebula, the stratum of Cancer proceeds towards the head of Hydra.

I have seldom contemplated a more brilliant and beautiful view in the heavens than one of the fields of view of this cluster of stars. With a 3 feet achromatic, and a power of 95, I have counted from fifty to seventy stars. Fifteen or twenty of the most brilliant of these presented beautiful configurations: one of them was an equilateral triangle; another an isoscelus; a third nearly of the figure of a cone; a fourth parallel lines, &c. In more than two instances, three brilliant equidistant stars appeared in a straight line, similar to the belt of Orion, while a considerable number of the remaining stars appeared extremely small. With a 6 feet achromatic, whose object-glass is 4 inches diameter, and a power of 110, this view was rendered still more brilliant. Several fields of view, nearly of description, be perceived in the clusver. Fig. 40 represents one of these views, in which some of the smaller stars are omitted. This view was taken with the 3 feet telescope, having an erect eyepiece. The configurations appear somewhat different in their relations to each other when viewed with an inverting eyepiece.

Another cluster is found in the sword-handle of Perseus, which is crowded with stars of a smaller size than in the clusters already noticed, and which requires a telescope of greater power to resolve them and show them separated from each other. Perseus is one of the northern circumpolar constellations, nearly opposite to the three stars in the tail of the Great Bear. A line drawn from these stars through the Polestar meets the sword and head of Perseus at nearly an equal

distance on the opposite side. It is directly north of the Pleiades, between Andromeda and Auriga. The sword is in the neighbourhood of Cassiopeia. A line drawn from Algenib, the brightest star in this constellation, to the middle of Cassiopeia, passes through the sword-handle where the cluster is situated, which is about midway between these two objects.

If the lowermost of the three small stars which form the sword of Orion be viewed with a good telescope, a beautiful configuration of stars will be perceived. Fig. 41* represents the principal stars comprehended in one field of view at this point, as taken with a six feet and a half telescope, with an inverting eyepiece, magnifying 110 times; it exhibits a distant resemblance of the whole constellation of Orion as seen