704
��Popular Science Monthly
��concrete, was greased with stearin, painted on hot, and the concrete was tied back to the sHngs.
The supporting structure for the aft portion of a ship must be removed before the launchings can take place (if the
WireSU,
���Ribband
��Fig. 1. Section through the fore part of
the supporting structure, starboard side
looking forward
stern dips into the water first), since the central portion of the hull has so much greater width. About six weeks before the Arizona was launched, the aft keel- blocks were removed and tumbling shores substituted. These consisted of blocks rounded ofif at their top, forward and bottom, after ends, thus allowing them to tumble when the ship started to move down the ways. This arrange- ment is illustrated in Figure 3.
The actual releasing of the ship was accomplished by means of two hy- draulicly-operated triggers, one on either side of the shell and operated together. The trigger, shown in Figure 4, consists of special forged steel, the upper end engaging a cap set in the sliding ways,
��and the lower end bearing against a piston, sliding in a cylinder fastened to the ground ways. The cylinder con- tained a thirty per cent mixture of glycerin and water. When the signal was given, a releasing valve was turned,
��_^ ^DtreclLOn. shi pdakes Balbm af
���Fig. 3. Tumbling shores
allowing the glycerin in the hydraulic cylinder to escape. The pressure in the cylinder being removed, the trigger swung on its pivot, disengaging the cap and allowing the ship to move down into the water.
The effectiveness of this arrangement was proved in the launching of both the New York and Arizona. No apprecia- ble strain was noticed any- where, though very careful observations were taken.
���Sivoru^
��fKston
Fig. 4. The hy- draulic trigger itself
���SiaUonary '^ays '^^
Fig. 2. View showing steel-plate slings under the narrow fore part of the vessel
��Keeping Beverages Fresh
BY a new patent process grape juice, wines or beverages made from fruit juices can be so treated that they will not become turbid and will not form a sedi- ment when stored. Also they are prac- tically freed from any sort of bacteria. The liquid, under regulated pressure and temperature, is passed through a finely divided mass of some material which will not dissolve or absorb mois- ture, such as corundum, gar- net or quartz, and at the same time subjected to an electric current. If the liquid to be treated is acid, the crushed material it is passed over must be electro-negative; if the liquid is basic or neutral, the material, must be electro-posi- tive. Alternating current is employed.
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