Does this mean that they are dying, or is it the first stage in the life-history of a star, immediately preceding the not altogether dissimilar Wolf-Rayet stage? We do not know enough yet about nebulae to answer this question. VIII MIRA, THE WONDERFUL STAR The head of Cetus, the Sea-Monster, is formed of three stars in a crooked line (α, γ, δ); and a little beyond them, as far from δ as that is from α, you may sometimes see another star, marked on the map by the name “Mira,” which means “Wonderful.” Watch it carefully, and if it is on the upward grade you will see it slowly brighten until it equals δ, then γ, and if you are lucky it may even approach α in brightness; and meanwhile it will pass from red to a clear orange-yellow; then it will wane once more and gradually be lost to view, though you can follow it much longer in even a small opera-glass, and you will notice that as it grows fainter the colour becomes deeper and deeper crimson. Unlike η Argūs with its one brilliant phase in two centuries, Mira waxes and wanes once in every eleven months, although there is a capricious uncertainty in both the period and the brightness which makes her a most fascinating object to observe. Sometimes the maximum brightness is several days earlier, sometimes later, than the average; sometimes she only equals δ, she has been seen to excel α; and no one can foretell exactly what and when her maximum will be. Quite a number of other stars have been discovered which behave like Mira, and anyone who wishes to contribute something to astronomical research without having to buy large and expensive instruments, or to study difficult problems, cannot do better than observe some of these stars, carefully comparing them night after night with stars in the neighbourhood. Here is a list of a few southern “variable stars of long period,” as they are called, all of which are easily visible at maximum brightness with a binocular, and some even without. A map should be made of the surrounding stars, and a list drawn up of those which are of the different magnitudes through which the variable passes. Every fine night the star should be compared with these, and recorded in a note-book as brighter than one, fainter than others, perhaps equal to another, and so on, several comparisons being made to check each other. When the variable passes out of the range of the binocular, this should be noted. The British Astronomical Association, which has a branch in Australia, has a Variable-star Section, and anyone who becomes a member will receive ready help and advice, and may have the pleasure of feeling that he is doing useful work in astronomy.