Art. II — On the apparent Changes of Place, Colour, 

 Size, and Figure of the Ileavenlj/ Bodies, — Bt/ G. W. 

 Jordan, Esq., A.M. F.R.S. 



All the celestial luminaries are observed to be subjected to 

 apparent changes of place, beginning at points below the zenith, 

 where no change is, and increasing at stations descending 

 towards the horizon. Of the sun and moon at considerable 

 elevations, the light is more or less white, but at lower altitudes, 

 these luminaries become tinged with dilute tawny colours, 

 and the sun, when so low that it may be viewed with the naked 

 eye, becomes of a brilliant yellow, which changes to a brilliant 

 red, of decaying brightness until the orb sinks below the horizon. 

 At equal altitudes, the moon exhibits similar but fainter colours. 

 As the sun declines, not only these changes occur of place, of 

 colour, and of quantity of light, but the disc itself also undergoes 

 considerable apparent changes, primarily of dimensions, and 

 subsequently of figure. Primarily a general enlargement of 

 disc appears, subsequently a contraction of vertical diameter, 

 accompanied with a more considerable extension of horizontal 

 diameter, and a change of upper and lower limbs from circles 

 to ellipses, the lower being considerably more eccentric than 

 the upper. In this state of approach to the horizon, the lower 

 limb occasionally suffers considerable fluctuations, and variations 

 of outline, contracting and enlarging in different points at the 

 same time. 



These changes of place, colour, brightness, dimensioas, and 

 figure, have been variously accounted for. As they occur at 

 the same stations, and under the same circumstances, they are 

 unquestionably to be referred to the same causes. Each how- 

 ever has been considered apart from the other, with other views 

 than that of ascertaining the true causes of each, or of all. 

 The change of place has been considered by astronomers with 

 a view to ascertain its amount at a given station, and from 

 this to estimate its variation and amount at other stations. 



