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 LVI. Intelligence and Miscellaneous Articles. 



ON THE DISENGAGEMENT OF HEAT OCCURRING WHEN ELECTRICAL 

 VIBRATIONS ARE TRANSMITTED THROUGH WIRES. BY DR. I. 

 KLEMENCIC. 

 ^TVtlE present research is concerned in the first place with the 

 -*- disengagement of heat which occurs when electrical vibrations 

 are transmitted through wires. For the experimental invest : gation 

 a method was used which consisted in placing close to the wire to 

 be heated the junction of a thermo-element constructed of fine wires, 

 and measuring the heating of the wire due to the radiation against 

 the junction by the thermo-current produced. The primary cir- 

 cuit furnished waves 3-3 m. in length, and consisted of two 

 brass disks 30 cm. in diameter, which were conuected by a linear 

 conductor with a spark-gap in the middle. An exactly similar 

 body constituted the secondary inductor, except that it had no 

 spark-gap, but the middle part of the linear conductor was formed 

 of the wires to be investigated. Two experimental wires were 

 interposed; the length of both together was at most 12cm., while 

 the whole linear part of the secondary inductors had a length of 

 89 cm. Experiments on the development of heat in wires led 

 thus to the question of the division of the electrical current in 

 vibrations. With regard to the circumstance that the disengage- 

 ment of heat in very rapid electrical oscillatious takes place almost 

 exclusively in the surface -layer, it seemed to the author not 

 unimportant to observe how in this case the intensity of the 

 radiation is related to the change of resistance of the heated wire, 

 and then further to investigate what is the value of this ratio with 

 constant current. Measurements have shown that with wires of 

 the thickness here examined (0-037 cm.) there is no appreciable 

 difference in this respect. The heat disengaged on the surface is 

 rapidly conducted to the interior of the wire. It follows from the 

 experiments on the disengagement of heat that the resistance to 

 the passage of very rapid electrical vibrations depends on the 

 magnetizability of the wire in question, and on the kind of wire ; 

 yet as regards the latter in a way differing from the constant 

 current. For several wires of different material 6 cm. in length 

 and 0*037 cm. in thickness, a heat is found in vibrations which is 

 approximately expressed by the following ratio : — 



Iron : german silver : brass : copper =10-5 : 1*75 : 1 : 1. 

 The number for copper is probably too large, as it was inserted 

 in the series after a correction which was only approximately 

 correct. 



If the formulae of Stefan are applied to these observations, 

 theory and experiment agree well in the combination german silver- 

 brass. The combination german silver-copper did not give con- 

 cordant values, which is partially due to the fact that in these 

 experiments all the conditions were not fulfilled which theory 

 requires. 



Taking Stefan's formula the number 111 was obtained for the 

 magnetic permeability of iron, and in another 73. The observations 

 Phil. Mag. S. 5. Vol. 35. No. 217. June 1893. 2 P 



