412 PROCEEDINGS OF THE AMERICAN ACADEMY. 



haze showed powerful polarization on near-by peaks, making it clear 

 that the haze was extremely heterogeneous. The conditions which 

 would produce stable water nuclei of strongly polarizing size on a clear 

 day would tend to reduce larger droplets to the similar order of mag- 

 nitude instead of leaving them to superimpose specular reflection. 



I am not disposed to suggest that in the polariscope we have a 

 meteorological tool of vast importance, but my preliminary observations 

 certainly show that it gives a most instructive view of the very early 

 stages of atmospheric nucleation, and especially if combined with rain- 

 band observations it should have material prognostic value as regards 

 comparatively local conditions. There is also a chance for forming a 

 clearer idea of the conditions of nucleation in the upper air, including 

 the very high altitudes, since polarization is manifest after the sun is 

 so far below the horizon as to illumine only the upper strata. I bring 

 the preliminary facts to notice here in the hope that some one with a 

 suitable location and opportunity for systematic observation may find 

 them useful as a guide to further work along this line. 



