12 A Short History of Astronomy [CM. t. 



ecliptic recedes from the equator towards the north, until it 

 reaches, about three months afterwards, its greatest distance 

 from the equator, and then approaches the equator again. 

 The time when the sun is at its greatest distance from the 

 equator on the north side is called the summer solstice, 

 because then the northward motion of the sun is arrested 

 and it temporarily appears to stand still. Similarly the sun 

 is at its greatest distance from the equator towards the 

 south at the winter solstice. The points on the ecliptic 

 (B, D in fig. 4) where the sun is at the solstices are called 

 the solstitial points, and are half-way between the equinoctial 

 points. 



12. The earliest observers probably noticed particular 

 groups of stars remarkable for their form or for the presence 

 of bright stars among them, and occupied their fancy by 

 tracing resemblances between them and familiar objects, etc. 

 We have thus at a very early period a rough attempt at 

 dividing the stars into groups called constellations and at 

 naming the latter. 



In some cases the stars regarded as belonging to a con- 

 stellation form a well-marked group on the sky, sufficiently 

 separated from other stars to be conveniently classed 

 together, although the resemblance which the group bears 

 to the object after which it is named is often very slight. 

 The seven bright stars of the Great Bear, for example, form 

 a group which any observer would very soon notice and 

 naturally make into a constellation, but the resemblance 

 to a bear of these and the fainter stars of the constellation 

 is sufficiently remote (see fig. 5), and as a matter of fact 

 this part of the Bear has also been called a Waggon and 

 is in America familiarly known as the Dipper ; another 

 constellation has sometimes been called the Lyre and 

 sometimes also the Vulture. In very many cases the choice 

 of stars seems to have been made in such an arbitrary 

 manner, as to suggest that some fanciful figure was first 

 imagined and that stars were then selected so as to represent 

 it in some rough sort of way. In fact, as Sir John Herschel 

 remarks, " The constellations seem to have been purposely 

 named and delineated to cause as much confusion and 

 inconvenience as possible. Innumerable snakes twine 

 through long and contorted areas of the heavens where no 



