Subject: What's the relationship between the height and the amount of charge in the 'waterdrop generator'?

Its about Lord Kelvin's Water-drop electrostatic generator 
(http://www.amasci.com/emotor/kelvin.html and 
http://zapatopi.net/kelvin/papers/on_a_self-acting_apparatus.html). I would 
like to know what the height of the droppers has to do with the amount of 
charge for a very important school paper (so I can take part in my exams!). 
I've build one my own and it works, even when the droppers are 5 cm above the 
upper cans (called 'inductors'). But I don't understand why it still works with 
this distance...Seperation of charges have to take place, so I thought that the 
droppers had to be very close to the 'inductors'. How does this work???

Re: What's the relationship between the height and the amount of charge in the 'waterdrop generator'?