lO BULLETIN OF THE LABORATORIES 



not too great, will be proportional to the heating effect producing it 

 and this in turn, to the oscillations in the wires ww' . The galvanom- 

 eter deflections become therefore a direct measure of the intensity of 

 the electrical oscillations.^ 



To avoid disturbing the wave system in the wires, Rubens did not 

 attach the wires ^v v^ from the dynamo-bolometer directly to the points 

 of the parallel wires to be investigated, but to little jars, made by plac- 

 ing around the wires bits of glass tube surrounded by shorter strips of 

 metal foil as " outer coatings," the wires themselves forming the "inner 

 coatings." With this apparatus, larger galvanometer deflections, ob- 



FlG. 2. 



tained when the bridge wire is at a node, correspond to the glowing of 

 the Geissler tube in Lecher's arrangement. 



The wave distribution along the parallel wires was studied as fol- 

 lows : The Leyden jars were placed over the ends of the wires, a 

 bridge of wire placed in a definite position across the wires (as shown 

 by a tape measure stretched below), current sent through the induc- 

 tion coil, and the galvanometer deflection produced by the heating of 

 the dynamo-bolometer read. This was repeated three or four times for 

 each bridge position, and bridge positions taken 5 to lo cm apart over 



I. Rubens and Paalzow, I. c, Vol. XXXVII, p. 529, (1889.) 



