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GENERAL REPORT OF THE JUDGES OF GROUP XXVI. 23 Its main truss, however, is higher, there being room under it for the passage of ordinary river steamers. 17. Fynje’s steam-pump, which is immersed in the water that it is charged with removing, is a very large, simple, double-acting pump, whose enormous valves give it a very large water-way, and reduce to a minimum the resistance chargeable to friction and to a disturbance of the flow. Its fitness for its work has been tested by ample experi ence. The advantages that it offers for the draining of polders, and all work where large volumes of water have to be lifted to slight ele vations, has led to its wide introduction in Holland, and entitle it to high consideration. It consumes but 1^ kilogrammes of coal per effective horse-power per hour. 18. There was an excellent illustration of the methods used in estab lishing the foundations of the railroad bridge over the Maas at Rotter dam, by the introduction of large iron caissons, sunk with compressed air to the hard ground beneath the mud. These caissons are sunk by the weight of masonry built upon them, and are thus gradually depressed to the hard bottom underneath the mud. When finally in position they are filled with concrete. 19. A model was shown of the ordinary lever draw-bridge, in uni versal use throughout the country, for passing foot-passengers and vehicles over canals. 20. In the illustrations of the water-works at the Hague—where water of the sand-dunes is collected by canals and filtered,—the in teresting feature is the elevated reservoir (which serves the purpose of a stand-pipe) at the top of a tall tower of masonry. An iron tank containing 1000 cubic metres stores fully the contents of an ordinary stand-pipe, and all at a high head. The rising main is only so large as is needed to supply this and to transmit the pressure to the pipes in the town. In the event of a cessation of the supply the stand-pipe head remains sufficient much longer than under the usual system. 21. The topographical maps, ordinance maps, etc., were all well executed and highly creditable. 22. Accompanying, and illustrating the exhibit, was an interesting series of photographs, showing the different stages of various impor tant railroad and hydraulic works, so taken as to give the clearest idea of the exact manner of executing them; for example, in connection with the construction of the new river from Rotterdam to the sea, by the means of sunken mattresses, the photographs show the different preliminary processes, and the final suspension of the ballasted mat tress over its position, attached to vessels by which it is surrounded, and from which the ballast has been supplied. When the tide is at