ELECTEICITY IN EELATION TO HORTICULTUEE. 



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thin galvanized iron wires from which the discharge will take place. : 

 With the high potential given by the Lodge-Newman apparatus ample 

 discharge will occur from a thin wire; with the influence machine it 

 may be necessary to add short points projecting downwards from the 

 wires. 



The distance apart of these wires depends upon the height the 

 network is raised from the ground; with a network ten feet high the 

 wires should probably not be more than twelve feet apart. > . , 



The shed in which the high tension current is generated should 

 not be far from the network so that little opportunity is given ^for 

 leakage in the passage of the charged wire from the shed to the outside 

 field. 



The wire should leave the shed under the shelter of a pent roof so 

 as to be protected as far as possible from rain, and it will preferably 

 issue through a fairly large hole as few insulators are so satisfactory as 

 air. Very good insulation is provided by passing the wire through a 

 quartz tube and mounting this on the top of a porcelain insulator, itself 

 mounted on the top of an ebonite rod or a glass rod that has been care- 

 fully paraffined when dry. 3! 



The wire that runs in this manner from the inside of the high ten- ' 

 sion shed to the overhead network should be quite short and be itself 

 covered with some insulating material, e.g. gutta percha or indiarubber. 



Overhead Discharge on Indoor Crops. 



Very httle work has so far been done in the application of this 

 method within greenhouses, but an experiment continued for some 

 years at Bitton enables some suggestions to be made as to how this 

 should be done. 



The shape of the house will be an important factor, and the wider , 

 ihe house the easier the arrangement of the discharge wires will be. 

 An important consideration is the position of the metal tubes used 

 for heating, and of all other conductors such as the wires used to sup- 

 port plants against the side of the house, etc. In houses where the 

 plants are always growing beneath or behind wires used to support 

 them, the method cannot be applied with any hope of success. 



With a narrow house it wilL probably be impossible to stretch more 

 than two wires down the length of the house, while in a broad house it 

 may be possible to arrange a grill-like network. In either case probably 

 the easiest way to support the system of wires will be to suspend them 

 by means of insulators and paraffined string from the sides of the 

 house ; the distance between a charged wire arid the side of the house 

 always being greater than the distance between the same wire and the 

 plants which it is desired to electrify. 



There should be some arrangement by which it is impossible to 

 enter a house when the inside wires are charged without either dis- 

 charging them or obtaining warning of the fact that the wires are 

 " live. " This may be managed when the doors open inwards by attach- 

 ing one support to the door so that wh^n the door opens; the . wire 



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