No. .">:! I'.'S. 



Suction Phenomena, Valves, Wind Wheels, Screw Flyers. 



409 



53123. 1: 11. 



53126. 1:7. 



53.1 ix. Sectional Model of a Membrane Valve, of metal, Figure 



53, 11 9. Sectional Model of a Safety Valve, with adjustable weight, of metal, Figure 



53,120. Robinson's Cross Cups, Models (M. T., Fig. 91) 



5.5.121. Windmill, of cardboard (M. T., Fig. 105) 



53.122. Screw Flyer (Propeller) free-flying, Figure (W. D. Figs. 183 and 184 [168 and 169]), 

 with throwing apparatus 



53.123. - - i d e m, flying upwards on. a 1 m long wire, thus obviating any damage to objects. 

 Figure 



53.124. Throwing Apparatus wound by a spring, Figure, with one screw flyer . . . . 



By winding up the spring to a greater or less degree it is possible to rcgnlutc the height to 

 which the flyer will ascend. The distance of ascent can be as much as 30 metres. 



53.125. 10 Screw Flyers for above, as spares 



s. d. 

 15. 



15. 

 6. 

 3. 



0. 6. 



16. 



rj. o 



53,126. Throwing Apparatus for Boomerangs, after Pfaundler, Figure, with 6 small alu- 

 minium boomerangs of different shapes (M. P., 10 th Edn. I, Fig. 327) 



0. 2. 



53,127. Boomerang (W. D. Fig. 185 [170]) 



53,1 2X. Model of a Parachute (M. T. I, Figs. 588 and 589 [605 and 606]) 



Wind Vane and Wind Wheel for demonstrating the Propeller Fan: see No. 52,006. 



1. 

 0. 

 0. 



X. 

 1. 

 8. 



Water Air Pumps: sec Nos. 50, 127 fiO,lor>, pp. 22 2~. 

 Anemometers and Wind Vanes: sec Meteorology. 



Cl. 1009, 1003, 1004, lOOo, 1006, 

 1010, 1011,4942. 



