144 Trans. Acad. Sci. of St. Lows. 
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. 
Magmtude 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, ete., 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 
