THE STARS FOR APRIL.

In the northern heavens (p. 98) we now see the Little Bear passing above the horizontal position which he had not quite reached last month. The Great Bear is now overhead, but inverted. The triplets of stars, √, μ, λ and 0, 4, K represent his paws, and I fear there is nothing better for his head than the small group v, 0, and 23. The dreary constellation Lynx occupies the position shown. It was not one of the ancient constellations, but was invented by Hevelius, just as Camelopardalis (the Giraffe) was invented, to fill up a waste space in the star-charts. King Cepheus is now immediately below the pole, but still in unkingly attitude. The stars y and x represent his feet, flourishing wildly upward; ¿, e, and 8, as I mentioned last month, represent his head; and marks the place of his left hand, in which he bears a regal sceptre. Admiral Smyth, in whose "Bedford Cycle" there is much curious information about the constellations, gives the following doggrel account of the true position of Cepheus, according to Aratus and Ptolemy:

"Near to his wife and daughter sec,

Aloft where Cepheus shines,
That wife, the Little Bear, and Swan,
With Draco, bound his lines;
Beneath the Pole-star twelve degrees
Two stars your eye will meet,-

Gamma, the nomad shepherds' gem,
And Kappa mark his feet.

Alphirk (8), the Hindu's Kalpeny,
Points out the monarch's waist;
While Alderamin (a), beaming bright,
Is on the shoulder placed;

And where, o'er regions rich and vast,
The Milky Way is led,

Three stars, of magnitude the fourth,
Adorn the Æthiop's head."

The story of Cepheus and his wife Cassiopeia, their daughter Andromeda, and Perseus, the gallant knight who rescued her from the sea monster (Cetus), does not belong to astronomy. But if it did, I should not venture to tell it here; for has it not been told already in Kingsley's charming poem Andromeda ?" How Perseus found means to gorgonize the sea monster with a petrifying stare is even more charmingly told in the "Tanglewood Tales," by the American prose-poet, Hawthorne.

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Cassiopeia is following Cepheus, a little to the left, or west, of the north. You can always find Cassiopeia by noticing that it is almost exactly opposite the Plough, regarding the pole as a centre. Thus 8 of the Great Bear, and a of Cassiopeia, are at the two ends, and the pole at the middle of a mighty arc on the heavens. Cassiopeia passes under the Pole-star in the same undignified position as her husband's. For you are not to suppose, as many (I find) do, that e, 8, and y form the back of Cassiopeia's chair, y and the seat thereof, and & and ẞ the ends of the chair's legs. These last are ate and y, while and ẞ mark the place of the top rail. Still, in its present position, the group forms a very fair picture of a rocking-chair, e, a, ß, and 4 forming the rockers. Next month I shall speak more particularly about this constellation.

The portion of the Milky Way now under the pole is very irregular. In the constellation Cygnus you will see a great opening in the Milky Way. This opening is sometimes called the Northern Coalsack, though it is not nearly as black as the opening in the southern Milky Way near the Cross, which is the real Coalsack.

The region in which the Northern Coalsack lies is shown in the map of the northern sky. But a special map is added in Fig. 16, for another purpose. In 1876 a new star appeared in the constellation Cygnus (the Swan). On the evening of the 24th of November, Professor Schmidt, director of the Athens Observatory, noticed a star of the third magnitude at the place shown by the skeleton star in Fig.16. Not only was no star of that brightness there before, or any star visible to the naked eye, but it was found when

catalogues and charts came to be examined, that no star had ever been noted there, even in lists meant to include all stars down to the tenth magnitude. For instance, Argelander

has made such a list, and charts from it, showing no less than 324,000 stars,—that is, a hundred times as many as we can see on the darkest and clearest night; yet his list showed no star where the new one had appeared. Astronomers did not, however, infer that the new star is really new, except in the sense of being seen for the first time. They knew that when last a new star appeared in this way it was found to be one of Argelander's army of 324,000 stars, and watching that star (which had appeared in the constellation of the Northern Crown in May, 1866), they found that though it faded gradually out of sight to ordinary vision, the telescope could still follow it, until it had sunk to the tenth magnitude, at which degree of lustre it remained and still remains. Possibly if we had had full lists of all stars down to the fifteenth, or perhaps the twentieth, magnitude, we should have found that the new star in Cygnus was simply an old faint star which had brightened up suddenly, and remained for a time as one among the stars adorning our skies.

Examined with an instrument called the spectroscope the new star gave a very strange account of itself. It was found to be emitting the same sort of light as other stars; but besides that light, it emitted such light as comes from intensely heated vapours. Among the vapours in that star thus (for the time) intensely hot, were hydrogen, the vapours of the metals sodium and magnesium, and a vapour known to be present in enormous quantities in our sun's outer atmosphere, as seen during times of total eclipse. All these vapours surround our sun; and it is very probable that if anything caused our sun to blaze out with greatly increased light and heat, people living on a world circling round some other sun would find the same peculiarities in our sun's light as we have found in the light of the new star in the Swan. What caused that star to blaze out in that strange way we do not know. We should like to know, because we might then determine whether the cause which had so disturbed that sun might not be one from which our own sun may one day