PHYSIOGNOMY OP PLANTS. 211 



But if the unassisted eye shows that life is diffused through- 

 out the whole atmosphere, the microscope reveals yet greater 

 wonders. Wheel-animalcules, brachioni, and a host of micro- 

 scopic insects are lifted by the winds from the evaporat- 

 ing waters below. Motionless and to all appearance dead, 

 they float on the breeze, until the dew bears them back to the 

 nourishing earth, and bursting the tissue which incloses their 

 transparent rotating (3) bodies, instils new life and motion 

 into all their organs, probably by the action of the vital prin- 

 ciple inherent in water. The yellow meteoric sand or mist 

 (dust nebulae) often observed to fall on the Atlantic near 

 the Cape de Verde Islands, and not unfrequently borne in 

 an easterly direction as far as Northern Africa, Italy, and 

 Central Europe, consists, according to Ehrenberg's brilliant 

 discovery, of agglomerations of siliceous-shelled microscopic 

 organisms. Many of these perhaps float for years in the 

 highest strata of the atmosphere, until they are carried down 

 by the Etesian winds or by descending currents of air, in the 

 full capacity of life, and actually engaged in organic increase 

 by spontaneous self- division. 



Together with these developed creatures, the atmosphere 

 contains countless germs of future formations ; eggs of 

 insects, and seeds of plants, which, by means of hairy or 

 feathery crowns, are borne forward on their long autumnal 

 journey. Even the vivifying pollen scattered abroad by the 

 male blossoms, is carried by winds and winged insects over 

 sea and land, to the distant and solitary female plant (4). 

 Thus, wheresoever the naturalist turns his eye, life or the germ 

 of life lies spread before him. 



But if the moving sea of air in which we are immersed, 

 and above whose surface we are unable to raise ourselves, 

 yields to many organic beings their most essential nourish- 

 ment, they still require therewith a more substantial species 

 of food, which is provided for them only at the bottom of 

 this gaseous ocean. This bottom is of a twofold kind : the 



p 2 



