484 MAcCCAUGHEY: THE STRAND FLORA. 
rents. Close to the shore, or where the water is shallow, the tem- 
perature of the water is higher when the surface is calm, but low 
when the sea is rough. This is the natural consequence of the 
solar radiation in the former case, and of the mixing by the waves 
of the surface water with the cooler water from below when the 
sea is disturbed. 
The annual thermal ranges of the oceanic waters of four repre- 
sentative regions will make a significant contrast with the condi- 
tions prevailing in Hawaiian waters: Sydney Harbor, Australia, 
55-8°-72.4° F.; San Francisco Bay, California, 42°-69° F.; 
Woods Hole, Massachusetts, below freezing—70° F.; Plymouth, 
England, 44.1°-58.9° F. 
The great oceanic current from the northeast, which travels 
down the Pacific Coast and out past Hawaii, as part of the Equa- 
torial Drift, has so profound an effect upon the Hawaiian climate 
in general and the littoral zone in particular, that it merits special 
consideration here. Dr. Sereno O. Bishop, who made Hawaii his 
home for many years, writes (’04) of this current, as follows: 
at remarkable stream of cold water, which flows ina vast stream southerly, 
skirting southeast Alaska, Vancouver’s Island, the Pacific States of Washington, 
Oregon, and California, and finally out westward to Hawaii, beyond whic 
group it becomes merged into the great equatorial current running westward. 
This stream is of very low temperature, of immense volume, and of great velocity. 
It is unique in its powerful effects upon the climates of the coasts along which it 
flows. . . . Finally turning westward like the trade winds under the impulse of the 
earth’s rotation, this mighty stream broadens out into the open ocean, gradually 
gaining warm 
Dall ( ‘04) states: 
As it moves down the coast it loses its heat and prod th d fogs of the 
Oregonian region, cooling off so that when it peaches the latitude of the ‘eetien Gate 
in late winter. This 
imparts to that favored group a uniformly subtropical climate such as is unknown to 
any other land in the same latitude. 
Cowles, in describing the strand of the Lake Michigan dune 
region (’99, p. 107), states that on the beach, due to the ‘‘absence 
of vegetation and the general exposure . . . the temperature is 
higher in summer and lower in winter than in most localities. 
This great divergence between the temperature extremes is still 
