Tide-Harnesser

At Keokuk, la., a vast power dam sprawls across the Mississippi River. Before it was built, many an engineer scratched his head ruefully, doubted that it could be done because of the vagaries of the banks of the Father of Waters.

At Niagara's Horseshoe Falls, there is an enormous power plant. Before it was built, engineers had gasped at the thought of such a thing.

At Muscle Shoals, Ala., the world's largest hydro-electric plant --600,000 h. p. in spring floods, 100,000 h. p. minimum--is now being built. Its construction is under the astute eye of Colonel Hugh L. Cooper, one of the two brothers responsible for the Keokuk and Niagara plants, not to mention various South American projects of great magnitude which they have designed, separately and together.

The other Cooper, Engineer Dexter P., sits on a forest of blue prints, surrounded by draftsmen and tidewater inspectors, in an office on Campobello Island near the head of the Bay of Fundy. About the island and up into bottlenecked bays, the fabulous tides of Fundy swirl in and out unceasingly, marking a difference of 27 feet between flood and ebb.

Mr. Cooper's blueprints contain his plans (published last week) for an ancient scheme never yet effected on a large scale--"letting the ocean do the work." Along the Pacific Coast one occasionally sees a battery of barrels or floating cylinders sapping a mite of Ocean's strength as they are slid up and down on ratchets by the incoming rollers. There are still visible along the Atlantic Coast, relics of crude paddle-wheel tide mills, which worked only with the falling tides and kept their operators up at annoying hours as the tide changed its time of fluctuation daily.

The Cooper plan transcends such feeble efforts as far as the locomotive outclassed the wheelbarrow. It calls for great sea walls, with water gates to shut the 100 sq. mi. of Passamaquoddy Bay into an upper pool. Other walls would immure Cobscook, the lower bay, 50 sq. mi. more. Across the inlet between the two pools thus formed, from Eastport* (island) to the Maine mainland, a dam and power house would be built. Operation would be as follows: on a rising tide, the gates to the upper pool would be opened to admit the sea. At flood, the gates would close. No water from the sea would ever enter the lower pool, its gates being opened only when its contents were above sea level. Thus there would be maintained a continuous fall of water over the power dam from the upper to the lower pool, a fall which Engineer Cooper estimates would produce a constant output of between 500,000 and 700,000 h. p. convertible into some 3,268 millions kilowatt hours a year. (Muscle Shoals, largest plant, turns out 700 million k. w. h. per yr.)

If the plant were built, its power would be enough to supply most of New England with light, heat and motivation. Maine has a law against the export of water power manufactured within her borders. But that law is thought only to restrict fresh-water power. At a popular referendum to be held in September, the people of Maine are expected to set the restriction aside from Cooper's Fundy plan. To induce the voters to do this, Mr. Cooper has placarded the state far and wide. Sanctions from the U. S. and Canada will also be forthcoming.

Engineer Cooper, who has for 14 years revolved his idea of riding the Old Man of the Sea and for four years studied the Fundy terrain, is prepared to finance his project without state or federal aid and to devote the rest of his life to its completion. It would cost over 75 millions, he figures. It would take 5,000 workmen five years. The sea walls necessary total over a mile in length and at to upper pool must be 70 ft. high. The power dam is 3,600 ft. To build in the concrete water gates, mountains of rock would have to be dropped in the tideways, some of which are 200 feet deep.

-Easternmost tip of the U. S. The westernmost is Cape Flattery, Wash., jutting to sea across the Strait of Juan de Fuca from Vancouver Island.