Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. It requires no description. Fig. 3 shows a tremendous ladle constructed for the North-Eastern Steel Company, for carrying molten metal from the blast furnace to the converter. It holds ten tons with ease. It is an exceptionally strong structure. The carriage frame is constructed throughout of 1 in. wrought-iron plated, and is made to suit the ordinary 4 ft. 8½ in. railway gauge. The axle boxes are cast iron, fitted with gun-metal steps. The wheels are made of forged iron, with steel tires and axles. The carriage is provided with strong oak buffers, planks, and spring buffers; the drawbars also have helical compression springs of the usual type. The ladle is built up of ½ in. wrought-iron plates, butt jointed, and double riveted butt straps. The trunnions and flange couplings are of cast steel. The tipping gear, clearly shown in the engraving, consists of a worm and wheel, both of steel, which can be fixed on either side of the ladle as may be desired. From this it will be seen that Messrs. Stevenson & Co. have made a thoroughly strong structure in every respect, and one, therefore, that will commend itself to most steel makers. We understand that these carriages are made in various designs and sizes to meet special requirements. Thus, Fig. 4 shows one of different design, made for a steel works in the North. This is also a large ladle. The carriage is supported on helical springs and solid steel wheels. It will readily be understood that very great care and honesty of purpose is required in making these structures. A breakdown might any moment pour ten tons of molten metal on the ground, with the most horrible results. * * * * * APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON THE SURFACE OF CONDUCTORS. Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple and ingenious apparatus which permits of demonstrating that electricity develops only on the surface of conductors. It consists (see figure) essentially of a yellow-metal disk, M, fixed to an insulating support, F, and carrying a concentric disk of ebonite, H. This latter receives a hollow and closed hemisphere, J, of yellow metal, whose base has a smaller diameter than that of the disk, H, and is perfectly insulated by the latter. Another yellow-metal hemisphere, S, open below, is connected with an insulating handle, G. The basal diameter of this second hemisphere is such that when the latter is placed over J its edge rests upon the lower disk, M. These various pieces being supposed placed as shown in the figure, the shell, S, forms with the disk, M, a hollow, closed hemisphere that imprisons the hemisphere, J, which is likewise hollow and closed, and perfectly insulated from the former. [Illustration]