24 PHILOSOPHICAL SOCIETY OF WASHINGTON. 
von Baer, had been plausibly explained as due to prevailing winds, 
but such action is purely or chiefly superficial, andsa less important 
factor in erosion than the behavior of thé main current, which is 
comparatively little influenced by winds. Nevertheless, he was 
surprised that the rotational influence admitted of so large a quan- 
titative expression. 
Mr. Dawu said that the northward-flowing rivers entering the 
Arctic ocean afforded at their mouths no evidence of the effect of 
rotation. The summer winds of Arctic regions are from the north- 
east and east, and these produce on the north coast of America a 
shore-current, which drifts the beach sand and shingle westward, 
and deflects the river-mouths in the same direction. All the rivers 
from the Mackenzie to Point Barrow illustrate this tendency. On 
the coast of Siberia the fresh water discharged by the large rivers 
has been observed to turn eastward, although the winds would 
tend to throw it the opposite way. The Arctic ocean is there 
deeper; and it is believed that its principal currents are controlled 
by the northeasterly set of the general currents of the North 
Atlantic. 
Mr. Rogprnson spoke of the indirect influence of wind on river 
channels, through drifting sand. "Mr. Hazen pointed out that the 
influence of wind might be eliminated from the problem by study- 
ing the streams running east or west. Mr. BourreLLe suggested 
that the course of the Mississippi did not indicate any result of 
rotational influence. Mr. E. FarquHar inquired whether the 
behavior of the Gulf Stream and other ocean currents was in accord- 
ance with the theory of rotational influence; and Mr. Dau re- 
sponded that in the discussion of ocean currents this cause had lately 
dropped out of sight, the determination of courses being ascribed 
to the winds. 
Mr. Mussey inquired whether the acuteness of continental 
masses toward the south admitted of an explanation based on the 
effect of terrestrial rotation; and Mr. Durron responded by saying 
that the mass of speculation in regard to the recurrence of certain 
forms of continental outline had never really accomplished more 
than the statement of the fact. The fact itself is an accident, 
dependent on the volume of the ocean and the general laws govern- 
ing the formation of mountain chains. If the ocean were five 
hundred feet deeper, or five hundred feet shallower, the forms of 
