One would very much like to know whether the movement of the sun is along a straight line, or in an enormous orbit around some centre. The idea has been put forward that it may be moving around the centre of gravity of the whole visible stellar universe. Mädler, indeed, propounded the notion that Alcyone--the chief star in the group known as the Pleiades--occupied this centre, and that everything revolved around it. He went even further to proclaim that here was the Place of the Almighty, the Mansion of the Eternal! But Mädler's ideas upon this point have long been shelved. To return to the general question of the proper motion of stars. In several instances these motions appear to take place in groups, as if certain stars were in some way associated together. For example, a large number of the stars composing the Pleiades appear to be moving through space in the same direction. Also, of the seven stars composing the Plough, all but two--the star at the end of its "handle," and that one of the "pointers," as they are called, which is the nearer to the pole star--have a common proper motion, _i.e._ are moving in the same direction and nearly at the same rate. Further still, the well-known Dutch astronomer, Professor Kapteyn, of Groningen, has lately reached the astonishing conclusion that a great part of the visible universe is occupied by two vast streams of stars travelling in opposite directions. In both these great streams, the individual bodies are found, besides, to be alike in design, alike in chemical constitution, and alike in the stage of their development. A fable related by the Persian astronomer, Al Sufi (tenth century, A.D.) shows well the changes in the face of the sky which proper motions are bound to produce after great lapses of time. According to this fable the stars Sirius and Procyon were the sisters of the star Canopus. Canopus married Rigel (another star,) but, having murdered her, he fled towards the South Pole, fearing the anger of his sisters. The fable goes on to relate, among other things, that Sirius followed him across the Milky Way. Mr. J. E. Gore, in commenting on the story, thinks that it may be based upon a tradition of Sirius having been seen by the men of the Stone Age on the opposite side of the Milky Way to that on which it now is.