284 On a Modified Water-dropping Influence-machine. 



From a wooden frame are hung by silk strings three simple 

 meta] vessels, the highest and lowest being rigidly con- 

 nected together with a stiff metal wire. The highest is a 

 small cylinder open at both ends ; the lowest is an open pot 

 which receives the water. The intermediate vessel is open at 



the bottom ; and is provided at the top with a funnel, the 

 upper rim of which is soldered inside the lip of the cylinder, 

 and its depth such that its central aperture is about at the middle 

 of the cylinder. An insulated wire, recurved as shown, is 

 carried up clear under the funnel in the middle vessel, and 

 should touch the drops as they fall below the aperture. The 

 water-jet, which must have a fine orifice, is inserted about half- 

 way into the uppermost vessel. A single point of water will 

 suffice to gather a plentiful charge. To watch the process of 

 charging two gold-leaf electroscopes may be connected respec- 

 tively to the middle and to the lowest vessels. 



The same arrangement will answer for sand-dropping if a 

 second, uninsulated funnel to contain the sand be provided 

 above the topmost cylinder, and arranged with its lower end 

 entering into the cylinder, so that the jet of sand breaks 

 away from the orifice at the proper height. As dry sand is a 

 very bad conductor, the apparatus is found to work with 



