316 Intelligence and Miscellaneous Articles. 



From our formula it further follows that, while light-energy be- 

 comes less for undulations with great waye-length X, and the energy 

 8, on account of the occurrence of currents, is complementary to 

 it, the greater X is the smaller does the latter energy become. 



As the loss of energy is proportional to the total energy, it fol- 

 lows that the same laws hold good for the loss of L and S. 



Let us now consider the expression 



We see that when h is small (as it is with bad conductors) jr, in- 

 creases with X increasing ; yet the absolute value is small ; so that 

 with them the light-energy and its yariation are approximately in- 

 dependent of the wave-length. 



p2 

 In bodies in which the polarization is small, — becomes =1 



nearly ; also L and S are then independent of the wave-length, and 

 L is nearly. 



In conclusion, let us consider the ratio r of the transmitted to 

 the incident light with a plate of \^hich the thickness is = I. The 

 amplitude of the distance I is AU=Ae-^^; and 



or 



-'^' e-^PK 



a^h'-Yh 



In perfect nonconductors (where &=0) /'becomes =1, conse- 

 quently all the light is transmitted ; in perfect conductors (where 

 rt = 0) it is all absorbed. If in r we replace a, h, Z-, jj» by their values, 

 we obtain for the relation betw^een the absorption and the quanti- 

 ties K, jj, C, A : — 



In insulators r must be independent of the ^Aave-length ; in 

 other bodies, under otherwise like circumstances .v increases with 

 the wave-length. — BdhVdtterzu Poggendorff's Annalen, 1877, Xo 7 

 pp. 409-413. 



ON SPECIFIC INDUCTIVE POWER. BY V. NEYRENEUF. 

 The inductive power of insulating substances, discovered by 

 Taraday, has been the object of numerous researches, all of which 

 bear upon the phenomenon of influence properly so called. One 

 might further ask, What modification in the energy of the spark is 

 induced by chaugiug the ]iature of the insulating plate of a con- 



