THE PLANETS URANUS AND NEPTUNE. 419

that, when they so pass, they are nearly in the same direction asseen from the Sun, or all nearly in a straight line drawn fromthe Earth . On the contrary, it is only a near coincidence intime that is referred to, while the Perihelia in question may hein very different longitudes in the heavens. This is shown inFig . XCIII., in which the various dates and positions of the

Fig. XCIII.—Positions J, s, u, x, of the Perhelia of the orbits of Jupiter , Saturn , Uranus ,and Neptune , between a.d. 1876 and a.d. 1887; and of the Aphelion of Jupiter in 1886.

Perihelia of the orbits of Jupiter , Saturn , Uranus , and Neptune ,which occur during several consecutive years, beginning with1876, are indicated. It is, however, impossible, with the scaleupon which the diagram is drawn, to represent the orbitsotherwise than as circles.

It is quite true, as the above figure indicates, that Jupiterpassed through Perihelion on September 25th, 1880 ; that