144 Trans. Acad. Sci. of St. Louis. 



the parched land there is in reality a steady and notable 

 advancement of soil materials in the direction of the pre- 

 vailing winds eventually transporting them far beyond 

 the boundaries of the arid tract. This exportation of 

 desert soil appears to be more rapid, more extensive, and 

 more constant than the flow of sediments in rivers from 

 an area of equal size. 



Black Sands of Desert Soils and Arctic Snows. 



Magnitude of Meteoric Augmentation. From the oc- 

 casionally recorded falls of the larger meteoric irons and 

 stones something of their nature has been made known. 

 Our prevailing conceptions of extra-terrestrial materials 

 are largely confined to such masses. In the broader 

 problems it is, however, the constant and almost imper- 

 ceptible shower of cosmic dust and smaller stellar parti- 

 cles upon the earth's surface that is of greatest conse- 

 quence. By this, and not by the rarer larger masses, 

 must the volume of cosmic augmentation to the earth's 

 bulk be measured. 



Not only the magnitude but the more common evidences 

 of the cosmic dust shower ordinarily escape notice. This 

 is especially true in countries with moist climates. In 

 the last mentioned situations, about the only direct sug- 

 gestion of such phenomenon is the fact that hailstones 

 are frequently found containing small particles of what 

 is presumably meteoric iron. 



In desert and cold portions of the globe the chances 

 of observation upon cosmic materials falling upon the 

 surface of the earth are much more favorable than they 

 possibly can be in moist countries. By the melting of 

 snow in the arctic regions fine metallic particles com- 

 posed mainly of iron, nickel, cobalt, etc., are obtained; 

 and their source often occasions wonderment. The 

 reality of the heavenly host and something of its impor- 

 tance may be gained when the frequency and numerical 

 extent of meteoric falls are taken into consideration. In 



