144 ELEMENTS OF STATIC ELECTRICITY. 



erly insulated. At each burner there is a break in the 

 circuit, so arranged that a short spark will pass through 

 the gas; the ends of the wire being attached to an 

 insulator fitted to the burner. 



With the battery there is a ground wire, and con- 

 nection with the gas pipe to complete the circuit; but, 

 with the machine, the circuit is made by two separate 

 wires, connecting the chandeliers with the balls sur- 

 mounting the Leyden jars. On account of the greater 

 intensity of static electricity, these wires must be thor- 

 oughly insulated with thick rubber tubing, wherever 

 they are liable to come in contact with the walls or gas 

 fixtures. With these arrangements properly made, it 

 is only necessary to close the switch, separate P and R, 

 to the full extent, turn on the gas, and put the machine 

 in operation. The resistance of the air between P and 

 R, being greater than the resistance of the wires and 

 the short breaks between their terminals at the burners, 

 the sparks take place at the burners, and the gas is lit. 



As to the expense, convenience, and efficiency of this 

 system, as compared with the battery system, only gen- 

 eral statements can as yet be made. The first cost 

 would probably be about the same; after which there 

 would be no further expense with the machine, which, 

 with proper care, should remain in good working order, 

 for this purpose, for an indefinite term of years; while 

 the battery requires frequent renewal of the fluid, and 

 occasional renewal of the zinc, besides cleansing and 

 amalgamating. 



As to efficiency, the greater intensity of the spark 

 from the machine will be evident, when we consider 

 that a machine of very moderate size will easily pro- 

 duce sparks three to five inches in length, while a very 



