Nov., 1935.3 CURRENT TOPICS. 683

operating temperatures. It can be welded to itself or to other leads of the nickle-chromium alloy by using wire as a filler rod.

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Plant to Make Rubber at IOO Degrees Below.-(Iiefrigerating Engineer, Vol. 30, No. 3.) Down to - 100“ F. will go the tempera- tures in one section of a new plant for manufacturing artificial rubber, it was announced by the duPont company in Wilmington early in August. Several years laboratory experiments have proved the commercial feasibility of this cold, the most intense to be used on a large scale in industry. It is a part of a scientific trend toward lower and lower temperatures, where important chemical changes can be made more readily than with heat which has so long been the chief source of man’s mechanical domination over natural forces. The 100’ cold will be used to separate from acetylene the substance mono vinyl acetylene, which is the base of synthetic rubber.

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The Passamaquoddy Tidal-Power Project.-(mechanical Engi- neering, Vol. 57, No. 9.) Capt. HUGH J. CASEY furnishes a brief statement on the largest utilization of power from the tides the world has seen. Located in the vicinity of Eastport, Maine, the project will provide for the generation of power by creating and maintaining a low level pool about 37 sq. miles in area in Cobscook Bay, by the construction of a series of dams, a power house, and an emptying-gate structure between Cobscook Bay and the Bay of Fundy. It is planned that the interior basin shall be maintained at or near low tide levels. As the tide rises and the difference in head between the sea and the basin exceeds 5 ft. the power house will be opened and power generated from the rising tide. The mean range of tide at this locality is approx. 18 ft. Power is likewise generated during falling tide. In the absence of an auxiliary means of generation of power, this arrangement would provide no primary power, due to the necessity of shutting down the power house during lower tide levels for 5 hr. intervals twice a day. Provision is made for a pumped storage plant near Haycock Harbor, 15 miles distant. Surplus peak power generated at the main tidal power plant at and near high tide is transmitted to a large pumping plant located on the sea near Haycock which pumps water into a large reservoir 125 to 135 ft. above sea level. During the shut-down periods of the main tidal power plant, this stored water is used to generate power at the Haycock power plant. The initial development will be adaptable to a much larger two basin development utilizing both Passamaquoddy and Cobscook Bays.

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