18 Trans. Acad. Sct. of St. Louis. 
ered, and previous results have been confirmed. The dif- 
ferences between th two sides of the angle are, however, 
less marked than those obtained when the plate was en- 
closed. It is, however, felt that additional attention must 
be given to this branch of the subject. There does not 
seem to be any reasonable doubt of. the existence of mo- 
mentum effects at the angle, but the action is complicated 
by other effects, some of which have not received suffi- 
cient attention to permit of discussion at present. 
For example, the effect of spark discharges of this 
character on a platinum wire of 0.005 cm. diameter may 
be cited. After such a wire had been in daily use for 
about three weeks as an angle-wire, it was found that a 
system of regular wavelets had formed over its whole 
length, of about 80 cm. The waves were very regular in 
form. The wave length was 0.090 cm. and the amplitude 
from crest to crest was 0.015 cm. The wire was under 
tension of 4 grams weight. The wet cloth resistances 
were in constant use, so that electrical oscillations were 
eliminated. These wavelets seem to be much more reg- 
ular in form than those described by Planté. This may be 
due to a difference in the conditions of the discharge. He 
is said to have used a continuous current from storage 
cells. 
That the linear velocity of the current particles in a 
conductor must be very great follows from the following 
considerations, which were pointed out by the author in 
1895 :” 
Imagine two conducting spheres having radii equal to 
that of the earth, or 6.37108 em. Let them be charged 
to potentials +25 and —25 volts. Connect them with a 
wire containing in circuit a 50-volt 1-ampere lamp, the 
resistance of the wire conductor being neglected. In order 
to maintain the potential difference on the two spheres 
constant, and thus maintain normal candle power in the 
lamp while all of this store of electricity is being used, 
7 Nipher. Electricity and Magnetism, p. 390, § 222. 
