68 THE ANALYST+ APPARATUS, ETC. A Water-Jet Blower of Simple Construction. S. M. Revington and I. G. Rankin. (Chenz. News, 1907, 96, 259.) - .4 bottle of 4 litres capacity is fitted with a tight cork having four holes, as shown in the figure. The tube A is constricted in the centre, and the water-jet delivers into it diagonally on to the constricted part. B is a syphon-tube, the flow from which is regulated by a, screw-clip ; and C is a safety-tube about 2 feet 6 inches high. Air passes out at D, which has a diameter of 2 inch. By turning on the water and closing the exit D, the pressure soon starts the syphon, and air and water escape by the safety-tube. The blast will then be found to be strong and steady. If A be provided with a side-tube, and the jet connected to A with rubber tubing, the apparatus can be used for circulating gas.The position of the jet may be adjusted by noting the height of water in the safety-tube, and the same holds in con- trolling the outfall by means of ;the clip, care being taken that the bottle does not begin to fill. A. R. T. Laboratory Apparatus for the Evaporation of Liquids by Radiation from above. H. J. S. Sand. (Jozmz. SOC. Chem. Ind., 1907, 26, 1225-1226.)-An im- proved substitute for a water-bath for the evaporation of liquids consists of a plate of fused silica, which is held above the basin containing the liquid by means of a clamp,THE ANALYST. 69 the cork linings of which have been replaced by.pieces of asbestos board. The silica, plate is heated to a high temperature by means of a small blast-burner with a spreader giving a flat flame.The burner is held on the same stand as the basin, but in a different plane, by means of a clamp attached to a short iron rod extending from the stand horizontally. The rate of evaporation, in the case of pure water, is about 50 per cent. faster than with water-bath with a good draught. For liquids of higher boiling-point, such as solutions containing sulphuric acid, the comparison is still more favourable. Liquids from which large quantities of crystals separate show a tendency to creep up the sides, and if the crusts of crystals be not con- tinually removed losses may occur by spirting. J. F. B. A Gas-Generating Apparatus. E. Muller. (C?t,em. ,%it., 1907, 31, 1257.)-The apparatus consists of a U-tube provided with glass stoppers and a side-tube, as shown in the illustration.The stopper a forms a small washing chamber for the evolved gases, which are discharged into the solution to be treated through the side-tube. The volume of the gas, and to some extent its pressure, may be regulated by operating the stopper b. w. P. s. A Filter-Tube. Porter W. Shimer. (Chem. Engineer, 1907, 6, 197-198.)- This consists of an ordinary carbon-tube 1 inch in diameter, and is provided I' a with a device for supporting the filter and pushing it out of the tube. This device is a glass tube, which passes through the stem of the filter-tube, and has a flattened, perforated bulb at its upper end (see figure). This flattened top is covered with a close-fitting disc of piano- or filtering-felt, on which paper-pulp is deposited. This pulp is readily prepared by acting on unwashed Swedish filter-paper, in a cerasin vessel, with hydro- chloric acid (specific gravity, 1.18) containing a little hydrofluoric acid. The resulting pulp is stirred up with distilled water, and is deposited under diminished pressure on the filter-felt in the tube. The filter is very effective and rapid even for fine precipitates, but is un- suitable for large precipitates of oxide of iron and alumina. It is useful in the washing of oxidisable precipitates, as air can be excluded. Where rubber is unobjectionable, the filter support may be made from sheet-rubber, ++ inch thick, and perforated with five small holes. A central hole then holds a glass rod long70 THE ANALYST. enough to use for pushing out the. filter. Three-quarter inch tubes are used for carbon filtrations, the felt and pulp being replaced by glass-wool and finely-divided asbestos. A. R. T. % * * * a +