140 COSMOS. 



the blossom, the organisms of tne vegetable world. The cele- 

 brated Spanish botanist, Cavanilles, was the first who enter- 

 tained the idea of "seeing grass grow," and he directed the 

 horizontal micrometer threads of a powerfully magnifying 

 glass at one time to the apex of the shoot of a bambusa, and 

 at another on the rapidly growing stem of an American aloe 

 (Agave Americana), precisely as 'the astronomer places his 

 cross of network against a culminating star. In the collective 

 life of physical nature, in the organic as in the sidereal world, 

 all things that have been, that are, and will be, are alike 

 dependent on motion. 



The breaking up of the milky way of which I have just 

 spoken, requires special notice William Herschel, our safe 

 and admirable guide to this portion of the regions of space, has 

 discovered by his star-gaugings that the telescopic breadth of 

 the milky way extends from six to seven degrees beyond what 

 is indicated by our astronomical maps, and by the extent of 

 the sidereal radiance visible to the naked eye.* The two 

 brilliant nodes in which the branches of the zone unite, in the 

 region of Cepheus and Cassiopea, and in the vicinity of Scorpio 

 and Sagittarius, appear to exercise a powerful attraction on 

 the contiguous stars ; in the most brilliant part, however, 

 between ft and y Cygni, one half of the 330,000 stars that have 

 been discovered in a breadth of 5 are directed towards one 

 side, and the remainder to the other. It is in this part that 

 Herschel supposes the layer to be broken up.f The number 

 of telescopic stars in the milky way, uninterrupted by any 

 nebulae, is estimated at 1 8 millions. In order, I will not say, 

 to realise the greatness of this number, but at any rate to 

 compare it with something analogous, I will call attention to 

 the fact that there are not in the whole heavens more than 

 about 8000 stars, between the 1st and the 6th magnitudes, 

 visible to the naked eye. The barren astonishment excited 

 by numbers and dimensions in space, when not considered 

 with reference to applications engaging the mental and per- 

 ceptive powers of man, is awakened in both extremes of the 

 universe, in the celestial bodies as in the minutest animal- 



* Sir William Herschel in the Philos. Transact, for 1817, P. II, 

 p. 328. 



f Arago, in the Annuaire, 1842. D. 459. 



