A NOVEL BREAKWATER.

Evening Star, Issue 4165, 3 July 1876, Page 4

A NOVEL BREAKWATER.

Mi* Dyer, C.E., recently exhibited to a meeting of gentlemen at "Wellington plans of a novel kind of breakwater. Mr Dyer's idea is to oppose to the advancing wave a wall not composed of a flat surface which wil' offer resistance to its approach, but a wall composed of longitudinal iron cells or tubesj the open»ends of which, closely fitted together, front the wave. These are secured to each other and kept in position by'being attached to very strong screw, piles, which have a.Verticle section ofan acute triangle, so that they oppose no resistance tb; the attack of the wave. This wall of hollow iron cells so attached extends in height ft om 2ft to 3ft below low water mark, to such height above high wuter mark as may" be found necessary.' The sectional aret> •-, of these cells to tie of such dimensions as may her hereafter -described. These cells so attached together, and of such length as may be found sufficient, extend backwards- towards at a given angle of elevation to tne horzoo. The The sides of these cells, may be veclangular or hexagonal, which in shape converge to each other at the shore or rear side of the said sea-wall, gradually diminishing in dimensions until the fltoerture at thp rear is not more than Of tlte a,«ea at the .sen front. sides of- the &rid< iron ceils aie to be

lilted tip with cement concrete, and the superficial face of the wall so constructed, will it is claimed, form a pier or jetty, that the sea cannot sweep away, or pass over, but which may be used as" a road for means of access to shipping sheltered from the sea by such wall or jetty. It is claimed that the front of this wall of hollow iron cells, the sides of which are of the thinnest structure compatible with the requisite strength, will offer the least po&sible obstruction to the face of the advancing wave, as the open mouths of T the cells will face the prevailing direction of the current of wave and wind to be opposed ia each specific case. It is claimed further that the wave in rushing with extreme violence into these partially closed and gradually rising cells will have its coherence so destroyed and cut up that it will encouti r the graduated and elasted obstruction of the atmosphere contained in each of the tu. But the rear of-the cells being partially open, the air will be expelled with more or less force, and thus the vast dynamical force of the water will be employed in compressing and expelling the air contained in some thousands of selfacting puematic breaks, and will not avail to disturb the surface of a harbor so protected. It is claimed that this process will be far cheaper ami mo'e rapidly constructed than solid walls of concrete, or a wall of masses of stone deposited in the usual form. It will also be apparent ihat immediately on the retreat of the wave the superincumbent air will rush into the orifices from which it has been so forcibly expelled, and then the structure will again constitute an elastic atmospheric wall against which waves may dash in vain. Mr Hardy-Johnston, C.E. (who wns present at Mr Dyer's request), said he was ready to pledge- his professional reputation as to' the plan's feasibility. In his opinion a breakwater, of this description could be erected for one-third less than the cost of a stoue or concrete construction, and in one tenth of the time. It would be only practicable, of course, where piles could be driven, and not on a rocky coast.