C. A. Chant — Reception of Electric Waves. 417 



The exploration showed that with the wire arranged as in I, 

 fig 7, there was present only the fundamental, perfectly formed 

 (see curve I, tig. 7). When the wire was moved along to the 

 position shown in II, the vibration was roughly in the funda- 

 mental mode, but very poorly formed, the highest reading 

 being but two-fifths of that in I (see curve II ). When, how- 

 ever, the receiving wire was moved along to the position shown 

 in III, the fundamental was well-formed and one-fourth more 

 powerful than in I. This shows that the position of the receiv- 

 ing wire is of importance, the greatest effect being given when 

 the middle of the wire is opposite the end of the antenna. 

 Abraham* has remarked that on account of the transversality 

 of the vibrations, there should be no radiation in the direction 

 of the axis of the antenna. Arrangement IY was to test this 

 conclusion; it was found that the receiving wire responded in a 

 decided manner, a well-formed fundamental being present one- 

 half as powerful as in I. The arrangement Y gave the curve 

 shown, the minima being at 180 aod 486, the maximum at 352, 

 corresponding roughly to the first harmonic of the wire. The 

 greatest reading was about one-fourth that in I. With a wire 

 bent in the same way but placed as in YI, the fundamental 

 oscillation proper to the wire and as powerful as in I was 

 exhibited. This is a rather striking result. The arrangement 

 YII, with the large metal plate at the center, was indistinguish- 

 able from I. That for YIII (the same as Y with the plate added 

 at the bend in the wire) gave the fundamental somewhat dis- 

 torted shown in curve YIII. In IX the coils had a diameter 

 of about 5'5 cms , and were 2 cms apart. In this case the fundamen- 

 tal was very roughly formed (see curve IX), with the reading at 

 the end of the coil twice as great as at the end of the straight 

 portion. This shows the " multiplication " effect utilized so 

 capably by Slaby and von Arco, though it was not nearly so 

 great as it would have been had the length of the coil been prop- 

 erly adjusted for resonance. In X the wire was half-length, i. e., 

 325 cms , and the fundamental w r as well-formed, half as powerful 

 as in I. 



5. Repetition of some of Slaby 1 8 Fundamental Experiments. 



The methods here used for determining resonant lengths and 

 for exploring the wires seemed well suited for repeating some 

 of Slaby's*f fundamental experiments, and my results in some 

 cases were somewhat different from those published. 



Each half of the oscillator consisted of a brass rod 3*4 mm in 



*M. Abraham, Ann. der Physik, ii, p. 32, 1900. 



f A. Slaby, The Scientific Basis of Spark Telegraphy, Elektrotechnische 

 Zeitschrift, "No. 9, 1902; Lond. Electrician, vol. xlix. p. 6, 1902. Also, Der 

 Multiplikationsstab, etc., Elektrotechnische Zeitschrift, No. 50, 1903. 



