1903.] HAUPT—DEEPER NAVIGABLE CHANNELS. 208 
eight of our most important seaports, where jetties have been built 
or proposed for channels of modern depth, foot up to $50,515,784, 
but the difficulty of securing the depth has necessitated in such 
cases a resort to dredging to create and maintain the channel. 
These new conditions have resulted in the construction of powerful 
sea-going hydraulic dredges with great capacity, and have in a 
measure revolutionized the practice of deepening by scour, as it is 
considered by some more economical to use the dredge without 
regulating works. In consequence it is found that the amounts 
expended and estimated to complete the approved projects at only 
four of our principal ports by dredging alone will aggregate 
$41,396,129, exclusive of the large additional sums required for 
maintenance. 
In view, therefore, of the important interests involved, the unre- 
liability of dredged channels, the inadequacy of twin jetties and the 
great cost, it would seem pertinent to inquire whether the profes- 
sion of engineering has reached its ultimatum in this department 
of science. Is it not possible to utilize to greater extent the 
boundless resources of nature for the purpose of creating deeper 
channels at our ports? 
The magnitude of these forces will be. better understood when it 
is shown that the sun as a prime mover evaporates approximately 
15,000 tons from each square mile of the ocean’s surface every 
twenty-four hours, so that his daily work upon the 150,000,000 
miles of water surface represents a load of two and a quarter trillion 
tons, a large portion of which is carried by the wind-driven clouds 
to the land where it is recondensed. Assuming the precipitation to 
be proportional to the ratio of land to water, there would be 562 
billion tons falling on the land surface, and taking the run-off at 
but 4o per cent., there results 225 billion tons of stored energy 
flowing down to the sea every day of the year, or, reducing this 
weight to its volumetric equivalent, we have nearly fifty cubic miles 
or 264,000 square miles of water one foot deep, an area greater 
than the State of Texas. 
This is the fluid solvent which, in the laboratory of nature, is 
daily applied to earth-sculpture, while the portion at work in the 
chemical and metallurgical laboratories of the interior is much 
greater than this. The former is all that is available for the avenues 
of domestic commerce, while the latter is the part which contributes 
to its tonnage by developing its products. 
