sy 
1887.] By [Haupt. 
The combination of this external barricade against the sand 
with the internal reaction dike for current concentration is 
shown in the chart of Galveston Harbor (Fig. 2), where the 
general direction of the movement is illustrated by the com- 
parative shore lines and by the sand caught and held in the 
former channel by the south jetty. At the New York entrance 
(Fig. 5) similar effects are observed. Here the flood is com- 
pressed under the shore of Coney Island, where the beach 
channel is found, while the various ebb channels wind over the 
bar to the southward, increasing in depth as they approach 
Sandy Hook. The phenomenally deep basin on the bar at the 
head of Gedney’s Channel is also seen. The plans as proposed 
for utilizing the existing natural forces for increasing the 
scour without obstructing any of the channels, are indicated 
by the heavy lines on the chart. 
THe BREAKWATER. 
Jetties as now constructed are frequently composed of rip- 
rap stone of small dimensions, which lose nearly half of their 
weight when immersed. Hence they are easily displaced, and 
the work disintegrates. At Galveston the brush and stone 
jetties shrank or subsided during construction 61 per cent. 
The plans of the author propose to overcome this serious de- 
fect by constructing the breakwater of béton or other material 
constructed in barges, or on floats in the back channels, where- 
by the resistance of large masses will be rapidly secured to 
oppose the flood and protect the ebb. But the details of this 
method of construction do not properly constitute a part of 
this discovery. What is claimed as meritorious in this com- 
munication, and upon which the judgment of the Society is 
desired, is: 
