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Rh center of the dam, the bottom being ten feet above sea level at the up-stream end and sloping to sea level at the toe. Across the up-stream or lake opening of this channel a concrete dam has been built in the form of an arc of a circle making its length 808 feet although it closes a channel with a width of only 285 feet. The crest of the dam will be 69 feet above sea level, or 16 feet below the normal level of the lake which is 85 feet above sea level. On the top of this dam there will be 14 concrete piers rising with their tops 115 5/10 feet above sea level, and between these there will be mounted regulating gates of the Stoney type. Each gate will be of steel sheathing on a framework of girders and will move on roller trains in niches in the piers. They will be equipped with sealing devices to make them watertight. Machines for moving the gates are designed to raise or lower them in approximately ten minutes. The highest level to which it is intended to allow the lake to rise is 87 feet above sea level, and it is probable that this level will be maintained continuously during wet seasons. With the lake at that elevation, the regulation gates will permit of a discharge of water greater than the maximum known discharge of the Chagres river during a flood.

"The Spanish Main" did not mean any part of the sea, but part of the mainland of America, including the Isthmus of Panama, and the northern extremity of South America. This was what the Spanish settlers called "Terra Firma," to distinguish it from the islands of the West Indies, and what Drake and Morgan meant when they spoke of "the Spanish Main." Later, this easily became confused with the word "main," meaning the sea. Gilbert, in his poem on the sack of Old Panama, uses the word in its former sense: