Polarization of Light scattered by Metal Particles. 4 59 



in nitrogen with an admixture or! iodine vapour, have been 

 studied. Au explanation for the effects obtained with moving- 

 streams of gas is given. 



Fluorite and crystalline quartz are slightly transparent for 

 the rays studied. Those exciting the fluorescence of the 

 water band pass more easily through fluorite than do those 

 exciting the nitrogen bands. For crystalline quartz the 

 reverse is probably true. Rays exciting a very faint fluor- 

 escence at about 2300 A.U.in purified nitrogen pass readily 

 through fluorite and crystalline quartz. Fused quartz and 

 mica are found opaque for all the rays exciting fluorescence. 



The ultra-Schumann radiations have been refracted. The 

 index of refraction of quartz for them is 1*75 x '08, indicating 

 that they lie on the long wave-length side of the quartz 

 absorption band. 



The radiation exciting the water band has been reflected. 



XLIX. On the Polarization of Light scattered by Spherical 

 Metal Particles of Dimensions comparable with the Ware- 

 length. By E. Talbot Paris, B.Sc, Physics Research 

 Student at University College, London'". 



A SOLUTION of the problem of the scattering of electro- 

 magnetic waves by a spherical obstacle has been given 

 by Professor A. E. H. Lovej. Lord RayleighJ has shown 

 that Professor Love's results admit of considerable simplifi- 

 cation, and has used the simplified forms to calculate the 

 polarization of the scattered wave when light is incident on 

 a transparent sphere having a refractive index 1*5, and of 

 dimensions comparable with the wave-length. In the present 

 paper similar calculations have been effected for the cases (1) 

 when the sphere is supposed to be perfectly electrically con- 

 ducting, and (2) when the sphere is composed of silver. In 

 the latter case the incident, light is taken to have a wave- 

 length of 550 /uytt. In both cases the calculations have been 

 made for spheres having circumferences not less than one 

 wave-length, and not greater than two wave-lengths. 



With a view to verifying the numerical results obtained, 

 observations have been made on the polarization of the light 

 scattered by uniform suspensions of silver. These experiments 

 are described in the last part of the paper. 



* Communicated by Prof. A. W. Porter, F.R.S. 



f Proc. Math. Soc.'Lond. vol. xxx. p. 30S (18 



| Proc. Roy. Soc, A, vol. lxxxiv. pp. 25-46 (1910). 



