One of the most interesting features of the moon, when she is observed with a good telescope, is the variety of colour presented by different parts of her surface.  We see regions of the purest white—­regions which one would be apt to speak of as snow-covered, if one could conceive the possibility that snow should have fallen where (now, at least) there is neither air nor water.  Then there are the so-called seas, large grey or neutral-tinted regions, differing from the former not merely in colour and in tone, but in the photographic quality of the light they reflect towards the earth.  Some of the seas exhibit a greenish tint, as the Sea of Serenity and the Sea of Humours.  Where there is a central mountain within a circular depression, the surrounding plain is generally of a bluish steel-grey colour.  There is a region called the Marsh of Sleep, which exhibits a pale red tint, a colour seen also near the Hyrcinian mountains, within a circumvallation called Lichtenburg.  The brightest portion of the whole lunar disc is Aristarchus, the peaks of which shine often like stars, when the mountain is within the unillumined portion of the moon.  The darkest regions are Grimaldi and Endymion and the great plain called Plato by modern astronomers—­but, by Hevelius, the Greater Black Lake.

The Sun.—­Observation of the sun is perhaps on the whole the most interesting work to which the possessor of a moderately good telescope can apply his instrument.  Those wonderful varieties in the appearance of the solar surface which have so long perplexed astronomers, not only supply in themselves interesting subjects of observation and examination, but gain an enhanced meaning from the consideration that they speak meaningly to us of the structure of an orb which is the source of light and heat enjoyed by a series of dependent worlds whereof our earth is—­in size at least—­a comparatively insignificant member.  Swayed by the attraction of this giant globe, Jupiter and Saturn, Uranus and Neptune, as well as the four minor planets, and the host of asteroids, sweep continuously in their appointed orbits, in ever new but ever safe and orderly relations amongst each other.  If the sun’s light and heat were lost, all life and work among the denizens of these orbs would at once cease; if his attractive energy were destroyed, these orbs would cease to form a system.

The sun may be observed conveniently in many ways, some more suited to the general observer who has not time or opportunity for systematic observation; others more instructive, though involving more of preparation and arrangement.