Haupt. ] 38 (Dee. 16, 
le 
The determination of the character, direction and relative 
intensities of the forces acting upon any harbor entrance, 
from a study of the submerged topography and other 
local physical features. 
. The discovery of the existence of typical forms in the 
sandy spits bordering the entrance, which will in general 
indicate the direction of the resultant movement. 
The recognition of the fact that the proper place for the 
ebb discharge, or channel over the bar, is as far removed 
as may be from the point of direct attack of the flood 
resultant, when the direction of the latter is not normal to 
the coast. 
The definite enunciation of the principle that the trend of 
the coast with reference to the cotidal line will in general 
indicate at once the proper position for defensive works. 
. The presentation of an original form (in plan) of breakwater, 
whereby the natural agencies are materially azded, with- 
out serious interference with either the flood or ebb forces. 
. A method of improvement whereby the internal currents 
are concentrated and conserved for more efficient scour 
after passing the gorge. 
2 
. A plan for utilizing the natural tendencies of the flood to 
cut a beach channel which shall be available for the lighter 
draught vessels. 
The enunciation of the principle that the cause of the an- 
gular movement of the ebb stream after egress is due to 
the general form of the exterior coast line, which causes 
a racing of the tidal crests, from the outer capes towards 
the bight of the bay, and that the flood components thus 
generated are the principal forces which build the bars 
and shift the inlets. This incessant semi-diurnal action of 
the flood is the controlling element in the forces affecting 
