CH. I] 



TROUBLES WITH THE MAGIC LANTERN 



49 



the line wire which is not grounded. In some cases one wire is 

 purposely grounded. In such cases great care must be taken not 

 to ground the other wire (see also fig, 266-267 689). 



77. There may be too much resistance in the circuit. Open 

 the rheostat wider, if it is adjustable (fig. 281), keeping an eye on 

 the ammeter to see when the current is of the desired amperage. 



FIG. 22. INCLINED AND VERTICAL CARBONS 

 IN THE CORRECT RELATIVE 

 POSITION. 



The upper carbon is positive and supplies the light in both cases. 



FIG. 23. CARBONS IN THE CORRECT RELATIVE POSITION FOR BOTH 

 DIRECT AND ALTERNATING CURRENTS. 



A Inclined carbons in the correct position for alternating current. 



B Inclined carbons in the correct position for direct current. 



C Carbons at right angles in the correct position for either direct or 

 alternating current. Direct current is indicated. 



D Carbons arranged in a V-shaped position. For this position alternating 

 current only is employed; and the crater on each carbon contributes to the 

 light. The V may be either in a vertical or in a horizontal plane. The ver- 

 tical arrangement is the more common. 



