438 A. M. Mayer—Method of investigating, ete. 
1. Discharge of large inductorium* between platinum points one 
mm. apart. No jar in the circuit. 
The platinum electrodes were neatly rounded and formed on 
wire ;°; mm. in diameter. After the discharge through the rotat- 
ing disc, nothing was visible on it, except a short curve formed of 
minute, thickly-set white dots; but, on holding the dise be- 
tween the eye and the light, it was found to be perforated with 
33 clean round holes, with the carbon undisturbed around their 
edges. The portion of the discharge which makes these holes 
lasts ;'; second, and the holes are separated by intervals which 
gradually decrease in size toward the end of the discharge, so 
discharge. The average interval between the spark-holes is 735 
laced in the circuit of the coil, and which is described below. 
he above numbers were determined as the average measures 
on six dises. It is here to be remarked that all of the dis- 
terminals of the secondary coil. 
After this discharge through the disc a very remarkable 
appearance is presented, the full description of which I reserve 
for a more extended paper. The discharge in its path around 
the dise dissipates little circles of carbon. ere are 91 of 
these circles, each perforated by 4,8, 2or1 holes. I shall here 
have to adopt a new nomenclature for the description of this 
complex phenomenon. I call the whole act of discharge of the 
coil, the discharge. Those separate actions which form the little 
circles by the dissipation of the carbon I denominate flashes, and 
the periorations in these circles I call sparks. The discharge 
in the above experiment lasts ,'; of a second. ‘The flashes at 
the beginning of the discharge are separated by intervals aver 
* The striking distance of this coil between brass points was 45 cm. 
