"Out of several hundred observed by Mr. Bishop, forty-five have small companions of a bluish, or greenish, or purplish color. Almost all of these are stars of the eighth to tenth magnitude; only once are both seen blue, and only in one case is the large one blue. In almost every case the large star is yellow. The color most prevailing is yellow; but the varieties of yellow are very great.
"We may assume, then, that the blue stars are faint ones, and probably distant ones. But as not all faint stars or distant ones are blue, it shows that there is a real difference. In the star called 35 Piscium, the small star shows a peculiar snuffy-brown tinge.
"Of two stars in the constellation Ursa Minoris, not double stars, one is orange and the other is green, both very vivid in color.
"From age to age the colors of some prominent stars have certainly changed. This would seem more likely to be from change of place than of physical constitution.
"Nothing comes out more clearly in astronomical observations than the immense activity of the universe. 'All change, no loss, 'tis revolution all.'
"Observations of this kind are peculiarly adapted to women. Indeed, all astronomical observing seems to be so fitted. The training of a girl fits her for delicate work. The touch of her fingers upon the delicate screws of an astronomical instrument might become wonderfully accurate in results; a woman's eyes are trained to nicety of color. The eye that directs a needle in the delicate meshes of embroidery will equally well bisect a star with the spider web of the micrometer. Routine observations, too, dull as they are, are less dull than the endless repetition of the same pattern in crochet-work.
"Professor Chauvenet enumerates among 'accidental errors in observing,' those arising from imperfections in the senses, as 'the imperfection of the eye in measuring small spaces; of the ear, in estimating small intervals of time; of the touch, in the delicate handling of an instrument.'
"A girl's eye is trained from early childhood to be keen. The first stitches of the sewing-work of a little child are about as good as those of the mature man. The taking of small stitches, involving minute and equable measurements of space, is a part of every girl's training; she becomes skilled, before she is aware of it, in one of the nicest peculiarities of astronomical observation.
"The ear of a child is less trained, except in the case of a musical education; but the touch is a delicate sense given in exquisite degree to a girl, and her training comes in to its aid. She threads a needle almost as soon as she speaks; she touches threads as delicate as the spider-web of a micrometer.
"Then comes in the girl's habit of patient and quiet work, peculiarly fitted to routine observations. The girl who can stitch from morning to night would find two or three hours in the observatory a relief."