24 
PRECIPITATION AND EVAPORATION. 
There is one branch of research which is of the utmost 
importance in reference to these questions, but which, from 
the great difficulty of direct observation upon it, has been less 
successfully studied than almost any other problem of physi¬ 
cal science. I refer to the proportions between precipitation, 
superficial drainage, absorption, and evaporation. Precise 
actual measurement of these quantities upon even a single acre 
of ground is impossible ; and in all cabinet experiments on the 
subject, the conditions of the surface observed are so different 
from those which occur in nature, that we cannot safely reason 
from one case to the other. In nature, the inclination of the 
ground, the degree of freedom or obstruction of the surface, 
the composition and density of the soil, upon which its permea¬ 
bility by water and its power of absorbing and retaining or 
transmitting moisture depend, its temperature, the dryness or 
saturation of the subsoil, vary at comparatively short distances ; 
and though the precipitation upon and the superficial flow 
from very small geographical basins may be estimated with an 
enteenth century so write it. In Hakluyt (i, p. 2), easterly is applied to 
place, “ easterly bounds,” and means eastern. In a passage in Drayton, 
“ easterly winds ” must mean winds from the east; but the same author, in 
speaking of nations, uses northerly for northern. Hakewell says: “ The 
sonne cannot goe more southernely from vs, nor come more northernely 
towards vs.” Holland, in his translation of Pliny, referring to the moon, 
has : “ When shee is northerly ,” and “ shee is gone southerly .” Kichard- 
son, to whom I am indebted for the above citations, quotes a passage from 
Dampier where westerly is applied to the wind, but the context does not 
determine the direction. The only example of the termination in -wardly 
given by this lexicographer is from Donne, where it means toward the 
west. 
Shakspeare, in Hamlet (v. ii), uses northerly wind for wind from the 
north. Milton does not employ either of these terminations, nor were 
they known to the Anglo-Saxons, who, however, had adjectives of direc¬ 
tion in -an or -en, ern and - weard , the last always meaning the point 
toward which motion is supposed, the others that from which it pro¬ 
ceeds. 
M e use an east wind, an eastern wind, and an easterly wind, to signify 
the same thing. The two former expressions are old, and constant in mean¬ 
ing ; the last is recent, superfluous, and equivocal. 
