When we look upon the multitude of heavenly bodies with which the celestial vault is strewed, our attention is naturally arrested by certain groupings of brilliant stars, apparently associated together on account of their great proximity; and also by certain remarkable single stars which have excessive brilliancy or are completely isolated from the rest. These natural groups seem to have some obscure connection with or dependence on each other. They have always been noticed, even by the most savage races. The languages of several such races contain different names for the same identical groups, and these names, mostly borrowed from terrestrial beings, give an imaginary life to the solitude and silence of the skies. A celestial globe, as we know, presents us with a singular menagerie, rich in curious monsters placed in inconceivable positions. How these constellations, as they are called, were first invented, and by whom, is an interesting question which by the aid of comparative philology we must endeavour now to answer. Among these constellations there are twelve which have a more than ordinary importance, and to which more attention has always been paid. They are those through which the sun appears to pass in his annual journey round the ecliptic, entering one region each month. At least, this is what they were when first invented. They were called the zodiacal constellations or signs of the zodiac--the name being derived from their being mostly named after living beasts. In our own days the zodiacal constellations are no longer the signs of the zodiac. When they were arranged the sun entered each one on a certain date. He now is no longer at the same point in the heavens at that date, nevertheless he is still said to enter the same sign of the zodiac--which therefore no longer coincides with the zodiacal constellation it was named from--but merely stands for a certain twelfth part of the ecliptic, which varies from time to time. It will be of course of great interest to discover the origin of these particular constellations, the date of their invention, &c.; and we shall hope to do so after having discussed the origin of those seen in the Northern hemisphere which may be more familiar even than those. We have represented in the frontispiece the two halves of the Grecian celestial sphere--the Northern and the Southern, with the various constellations they contain. This sphere was not invented by the Greeks, but was received by them from more ancient peoples, and corrected and augmented. It was used by Hipparchus two thousand years ago; and Ptolemy has given us a description of it. It contained 48 constellations, of which 21 belonged to the Northern, 15 to the Southern hemisphere, and the remaining twelve were those of the zodiac, situated along the ecliptic.