A special department in the establishment of Messrs Denny, and an entirely novel feature in a private shipyard, is the experimental tank, already referred to in the Chapter on scientific progress. This notable section of Messrs Denny’s works may be described as consisting of a basin 300 feet long, 22 feet wide, and containing 9 feet of water over the principal portion of its length. Around this basin are the shops and appliances for the work which has to be done—constructive, experimental, and analytical. This work on the constructive side consists of making paraffine models, which represent on an appropriate scale the ships to which the experiments have reference; the paraffine is melted, cast in a rough mould to the approximate shape, and afterwards faired off by a specially-constructed and very ingenious cutting machine. When finished the model is passed on to the second stage—the experimental. A stationary engine draws a carriage along a railway suspended above the water space, the carriage is accompanied by the model, with an attachment which allows the model to move freely, and at the same time to depend entirely for its propelling force upon a spring carried by the carriage. The extensions of this spring are measured and recorded automatically, so too are the speeds, the record being made by electric pens in the form of diagrams, on a revolving cylinder which is part of the apparatus of the carriage. The analytical work consists of obtaining from the diagrams the items of speed and propelling force, the relation between which, at all speeds for which the experiments have been made, is thus obtained. The facilities which are offered by the tank for investigating to the utmost the laws of hydrodynamics in so far as they affect, practically, the resistance of ships, is thus obvious. On the facade of the tank, fronting the public street, Messrs Denny have placed an admirably-sculptured medallion portrait of the late Mr William Froude, of Torquay, the noted experimentalist. Underneath is the following inscription:—“This facade of the Leven Shipyard Experimental Tank is erected in memory of the late William Froude, F.R.S., L.L.D., the greatest of experimenters and investigators of hydrodynamics. Born 29th November, 1811. Died 14th May, 1879.”