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. 



