The stability balance consists of a frame =A= attached to a steel bar =Z=, having knife edges working upon the support =C=; a table =D= attached to a spindle working freely in the bearings =E=, and capable of being turned through any angle; a sliding weight =F= to balance the weight of the model when empty; a sliding weight =H= to balance and measure the weight of the water contained in inside or displaced by outside models; a sliding balance weight =K= which by adjustment will locate the centre of gravity of the combined weights of the table =D=, the model and the weight =K= in the axis of the table =D=, so that the model will remain when empty in any inclined position, and be balanced by the weight =F=. In order to determine the moments of stability, the model is first fixed on the table =D=, and the weights =F= and =K= so adjusted that =F= will balance the model at all inclinations. The table is then brought into the upright position, and water is poured into the model to the height corresponding to the desired draught of water, and the weight =H= shifted until the whole is balanced. The weight of water in the model will evidently be = weight =H= × its distance from the fulcrum ÷ distance centre of model is from fulcrum. If the table with the model is now turned through any angle, the distance the centre of gravity of the water has moved from the axis =E= of the table can easily be determined by shifting the weight =H= until the whole is balanced, then evidently from the principles of the lever, =H= × by its distance from fulcrum = weight of water in model × by the distance the centre of gravity of the water in the model is from fulcrum. Since the weight of =H= × its distance from fulcrum ÷ the weight of water in model is known, the distance that the centre of gravity of the water has shifted from centre line is easily ascertained and the righting lever determined. From a lengthened series of experiments, conducted by Mr Heck—latterly in Messrs Denny’s Works where an apparatus from a special design by Mr Heck has been constructed for the firm’s use—the method gives promise of taking a firm place as an extremely simple and approximately accurate means of arriving at the stability of vessels.[18]