18 



Mr. 0. J. Lodge. Experiments on 



[June 4, 



The jars being gallon jars, standing on wooden table. Compared 

 A and B sparks ; B was very long. Then substituted short wires 

 for the long ones, and compared again. B was nearly as short as A. 

 Readings follow : 



Overflow of Plate Condenser. 



20. Connected a pair of tea-trays to the machine by long thick 

 wires, and fixed them parallel to one another, keeping them asunder 

 by glass or paraffin pillars ; the jars standing on a wooden table, or 

 being otherwise leakily connected so that they might charge. Every 

 machine spark at A (fig. 9) caused long brushes, or sometimes re- 

 markably long flashes between the plates. 



FIG. 9. 



A jar standing on bottom plate will receive a flash, but it will not 

 necessarily be thereby charged; a slight residual charge may be 

 found in it, but no more. 



Points also get struck, just as noisily as knobs, and no more readily. 

 Crowds of points, and knobs of all sizes, get struck equally well, if 

 of the same height and all equally well connected to the bottom 

 plate. The highest gets struck at the expense of the others. Often, 

 however, several get struck at once. A gas-flame burning on the 

 bottom plate gets struck at a much greater distance than does any 

 metallic conductor. The weak hot-air column is precisely what this 



