Vehicle tunnel to be built under maas river at Rotterdam

been designed and built by the author. The main feature of this apparatus is that the flow takes place between two flat surfaces set so close together that considerable air velocities can be used, and little protection is necessary to maintain parallel flow. A box 48 X 7 X 12% inches contains the apparatus. Two plates of glass at-e fitted horizontally on this box so that there is a $$ inch deep and 12 inch wide channel between them. This channel connects the inlet and outlet compartments of the box at the ends. Arrangement is made so that smoke from titanium tetrachloride flows in the channel between the glass plates. Rubber models of various shapes and sizes, cut to the thickness of the channel are placed in the channel and streamlines can be observed around them. This is best accomplished by lighting from beneath the glass plates. Satisfactory photographs have been taken by a camera with illumination from either the top or the bottom. K’hile the results obtained by such an apparatus are largely qualitative, they have a wide practical application in addition to their usefulness in illustrating the principles of fluid flow. R. H. 0. Vehicle Tunnel to Be Built Under Maas River at Rotterdam. -(Engineering News Record, Vol. 118, No. 21.) Plans for the construction of this tunnel which separates two sections of the city of Rotterdam, Holland, call for a tunnel 2,295 ft. long exclusive of shore approaches. It is to be built by sinking ten preconstructed sections in line and joining their ends under water and will have a capacity of 5,2oo,ooo vehicles a year besides bicycle and pedestrian traffic. Construction, it is expected, will be completed by January 1941.

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