Chemical Dissociation and Electrical Conductivity. 437 
which the wave-velocity was 172x10° ems./sec. with a 
certain wireless transmitter, the wave-length on the helix 
was found to be 65 cms. Hence the frequency of the oscilla- 
tions used was 172 x 10°/65 = 2°65 x 10°, and the corresponding 
Jength of the “wireless wave” is 377 feet. Since the 
capacity used in the spark-circuit was 0°006 mfd., this 
measurement also tells us that the effective inductance of the 
oscillation transformer employed with it was 600 centimetres. 
By noting the increase in the wave-length on the helix pro- 
duced by adding a small riocline eeee or capacity to the 
oscillating circuit, it is obvious that the values of this addition 
can be sella In this manner the inductance of a foot 
or two of copper wire coiled into one or two turns can easily 
be measured. 
XLII. CRoriiecl Die citon and Electr ical see, By 
A. E. GARRETT and R. 8S. Wittows, B.A., D.Sc.* 
N the Philosophical Magazine for July 1899 there 
appeared a paper by Beattie entitled “ eae of Hlec- 
tricity from Plates.” When various mixtures of substances 
were placed on the insulated plate of an air-condenser and 
heated, it was found that a leakage of electricity took place, 
this being, in several cases, apparently independent of the 
sien of the charge. The temperatures used were between 
300° and 400°. Similar effects were obtained if the substances 
were placed on the earthed plate. 
Shortly after the appearance of this paper one of us 
repeated the experiments and verified the results generally. 
The apparatus used was similar to Beattie’s. It was found, 
how ever, in a good many cases, that the rite) of Teak de- 
pended in a gre eat measure on the sign of the charge given 
to the insulated plate. In a later papert+ Beattie found the 
same result. He showed that if positive electricity leaked 
from the plate when the substance was on it, then it was 
incapable of holding a negative charge when that substance 
was transferred to the earthed plate of the condenser. 
The objects of the experiments described in the following 
paper were to discover the origin of the leak, or, in terms of 
the ionization theory, to find out the seat of the ionization, 
and also obtain information concerning the nature of the 
ions in some of the cases. Asa good many of the new ob- 
servations and facts have been anticipated j in Beattie’s second 
paper, only those are given which bear directly on these 
objects. 
* Communicated by the Physical Society : read June 24, 1904. 
y+ Phil. Mae. April 1901. 
