VARIABLE ASPECT OF THE HEAVENS. 139 



Sun and Moon. The beautiful stars of the Centaur and of 

 the Southern Cross, will at some future day be visible in 

 our northern latitudes, whilst other stars (Sirius and the 

 stars forming the belt of Orion) will no longer appear 

 above the horizon. The place of the North Pole will be 

 successively marked by /3 and a Cephei, and 5 Cygni, until 

 after the lapse of 12000 years, when a Lyra will become 

 the brightest of all possible pole stars. These statements 

 serve in some degree to realise in the mind the magnitude 

 of the movements, which proceed uninterruptedly in infi- 

 nitely small divisions of time in the great Chronometer of 

 the Universe. If, for a moment, we imagine the acuteness 

 of our senses preternaturally heightened to the extreme limits 

 of telescopic vision, and bring together events separated by 

 wide intervals of time, the apparent repose which reigns in 

 space will suddenly vanish ; countless stars will be seen 

 moving in groups in various directions ; nebulae wan- 

 dering, condensing, and dissolving like cosmical clouds ; 

 the milky way breaking up in parts, and its veil rent 

 asunder. In every point of the celestial vault we 

 should recognise the dominion of progressive movement, 

 as on the surface of the earth where vegetation is con- 

 stantly putting forth its leaves and buds, and unfolding 

 its blossoms. The celebrated Spanish botanist. Cavanilles, 

 first conceived the possibility of " seeing grass grow," by 

 placing the horizontal micrometer wire of a telescope with a 

 high magnifying power at one time on the point of a 

 bamboo shoot, and at another on the rapidly unfolding 

 flowering stem of an American aloe ; precisely as the astro- 

 nomer places the cross of wires on a culminating star. 

 Throughout the whole life of physical nature in the organic 



