“ It receives the Delaware River, whose estuary gradually emerges into the bay. It is about 40 miles long to where it contracts to a width of 4 miles. Its greatest width is 25 miles, and the width at the entrance, between Cape May, in New Jersey, and Cape Henlopen, in Delaware, is about 15 miles. The depth of the channel varies from 30 to 60 feet, but much of the bay has less than 30 feet of water. A breakwater at Cape Henlopen, constructed by the United States Government, forms a large and safe harbor from 24 to 35 feet deep. ”