200 J. A. POLLOCK. 
Drude in the Annalen der Physik, 9, 2, p. 293, 1902, 
‘publishes an account of an elaborate research on the 
vibration period and self-induction of wire coils in con- 
nection with the construction of Tesla transformers. On ~ 
p- 328 he gives the results of the investigation with coils 
with few windings and with single circles. Drude does 
not measure the period of the vibration connected with 
straight wires, but states that for a thin straight wire the 
half wave length is equal to the length of the wire. He 
refers to a calculation of Abraham,’ which gives the half 
wave length 0°85% greater than the wire length, for a 
straight wire 0°25 cms. in diameter and 77 cms. long. 
In the present experiments the comparison of the periods 
has been made in all cases between circuits constructed of 
copper wire 0°33 cms. in diameter and rectangles of thin 
brass wire 0°04 cms. thick, the rectangles being 30 cms. 
wide. It is found that the perimeters of the rectangles 
are greater than twice the length of straight wires which 
have the same period of electrical vibration, the ratio of 
the lengths varying from 2°45 for a rectangle 760 cms. in 
perimeter to 2°31 for one whose perimeter is 1,200 cms. 
Approximately at least, the wave length of the electrical 
vibration associated with narrow rectangular closed circuits 
may be taken as equal to the perimeters of the rectangles. 
It appears then, from these experiments, that the wave 
length of the oscillation connected with a straight wire is 
much greater than twice the length of the wire, a result 
opposed to Slaby’s conclusions and to Drude’s statement. 
For open circular resonators Sarasin and De la Rive’ 
obtain results which are usually stated by saying that the 
wave length of the free electrical oscillation connected 
1 Abraham—Wied. Ann. LxXvt., p. 471, 1898. 
2? Sarasin and De La Rive—Comptes Rendus cx., 1890; cx1r., 1891; 
cxv., 1892. nia h maid . 
