ROLLING DAM IN MEXICO, ONE STEEL CYLINDER LOWERED. THE OTHER RAISED. DAMS OF STEEL IN the irrigated Laguna district of the Nazas River valley of Mexico, steel cylinders are being used for dams where the construction of water storage reservoirs and the control of the flood of water in the large irrigation canals are necessary. This type of dam is said to be FOR CUTTING METAL WITH GAS. A fine spray of oxygen cuts like a knife through the heated substance-an English invention. specially adapted for use in streams which are given to sudden rises, as the cylinders may be raised and lowered. The first of these rolling dams, as they are called, to be erected in Mexico was located on the San Marcos plantation, near Torreon. The dam is composed of two cylinders, each sixty feet long and eight feet in diameter. The cylinders form a water-tight reservoir when in place. A second dam of larger size, the cylinder being ninety feet long and twelve feet in diameter, has been constructed in the same district, at a cost of about $250,000. The cylinders are easily operated by electric power. They are raised or lowered on heavy racks, set in masonry abutments. Each cylinder is operated as an independent dam. The power equipment is placed on a masonry pier in the center of river or canal. A MODEL TOY MOTOR BOAT AS IT TOOK PART IN A "REGATTA" IN VICTORIA PARK, LONDON. MOVING TRUNKS BY ANYONE who has watched the bag gage men at our railway stations tugging the great truck load of trunks about can not help feeling that a partial relief at least from their strenuous labor is due them if some invention will make it possible. That this feeling has been shared by railroad officials is demonstrated by the development of a motor driven baggage truck shown in the illustration. Two styles have been designed, one much resembling the flat truck we are accustomed to seeing on station platforms, the other having a drop frame as shown in the picture. The latter style is for use at stations where the platforms are on a level with UNUSUAL TYPE OF BORING MACHINE IN USE IN SOUTH AFRICA. The machine is compact and comparatively small, and yet has tremendous power. invention of what is called the radiation pyrometer, an instrument which measures, with the greatest accuracy possible, the temperature of the interior of a furnace, although located on the outside and at a distance of several feet from the source of the heat. If two different metals are joined together and their junction heated, there will be an electric current developed which will flow in a circuit, if one is provided. The more the point of junction is heated, the more current is produced. When we introduce. into this circuit an instrument for meas uring the amount of electricity generated, and instead of marking the scale to read in volts or amperes, we arrange it to indicate degrees of heat, then we have a heat measuring instrument which may be near or far from the heat source, and yet secure the same accurate result. With the instrument shown in the illustration, p. 249, the temperature of a stream of molten iron is being taken, although the instrument is some distance from the furnace. In like manner the temperature of a steel billet may be taken as it passes between the rolls which form it into a rail. |
