314 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



and passing under the silk, to fly off at its edges. To collect 

 the fluid, place the conductor with its points about a quarter 

 of an inch from the edge of the silk, which will so readily 

 attract the fluid from the cylinder, that sparks proportionate 

 to the extent of the glass surface rubbed may be taken from 

 it ; being very careful, however, that the glass stand of the 

 conductor be perfectly dry. The pressure of the cushion 

 against the cylinder is to be regulated by the screw on the 

 stand at bottom. 



If the machine be small, it will require warming ; the 

 power of a machine is generally increased by rubbing the 

 cylinder for a minute or two with a slightly greased rag, or 

 by putting one hand upon the cushion. 



The rationale of the action going on, is this : The fluid 

 passes from the earth through means of the floor, Avails, &c., 

 to the chain suspended from the cushion ; here friction, winch 

 is the cause of the disturbance, takes place. The disturbed 

 fluid passes to the glass cylinder, and is confined from escape 

 by the silk flap ; that ceasing, the fluid would fly to any- 

 thing around, particularly to a pointed body, or a lighted 

 candle ; but this is prevented by the superior attraction for 

 it from the nearer end of the prime conductor put to receive 

 it. Thus it will be at once seen that- an electrical machine 

 resembles a pump ; the earth may be likened to a well of 

 water ; the chain to the lower pipe of a pump ; the cushion 

 is the sucker ; the silk the nozzle ; and the prime conductor 

 is like a pail to hold the fluid. Price, 5-inch, $10.00. 



" 6-irich, $12.00. 

 " 8-inch, $16.00. 



