The study of variable stars is one which should seem to be specially reserved for the amateur observer. In general, it requires but little instrumental equipment. Many variables can be seen at maximum, some even at minimum, with the unaided eye; in other cases a good opera or field glass is all that is required, and a 2-1/2 or 3-inch telescope will enable the observer to command quite an extensive field of work. Here, again, the beginner may be referred to the _Memoirs_ of the British Astronomical Association for help and guidance, and may be advised to connect himself with the Variable Star Section. With the exception of such variations in the lustre of certain stars as have been described, the aspect of the heavens is, in general, fixed and unchanging. There are, as we shall see, real changes of the vastest importance continually going on; but the distances separating us from the fixed stars are so enormous that these changes shrink into nothingness, and the astronomers of forty centuries before our era would find comparatively little change today in the aspect of the constellations with which they were familiar. But occasionally a very remarkable change does take place, in the apparition of a new or temporary star. The accounts of the appearance of such objects are not very numerous, but are of great interest. We pass over those recorded, in more or less casual fashion, by the ancients, for the reason that the descriptions given are in general more picturesque than illuminative. It does not add much to one's knowledge, though it may excite wonder, to find the Chinese annals recording the appearance, in A.D. 173, of a new star 'resembling a large bamboo mat!'