EXPERIMENTS WITH lOTVIZED AUt. 



23 



order of colors, is borizontally asym[)totic with its concavity upwai'd. Toward tlie 

 left of opaque the browns of the fii'st ordei- make a very I'apid ascent, suggesting 

 a vertical asymptote. If one is led to infer that the latter are due to the scatter- 

 in"- of fine particles set forth in Rayleigh's dynamics of the blue sky, whereas the 

 others are diffi'actions or intei'ferences (Clausius) of the more neai'ly regular 



Figs. 3, 4.— Charts Showing the Relation ok the Relative Number of I'articles (Dust Contents) 

 TO THE Color Produced, E.xi'Ressed in Thicknesses (Air) of Newton's Interference Plates. 



kind (i. e., cases where the particles oi' vesicles ai'e large enough to be subject to 

 the ordinary optical laws), the continuity of curve from either side of opaque is 



baffling. 



There is further difficulty in making a comparison of the data as a whole, 

 seeing that one arbitrary element must enter the work even if the jet action and the 

 ionizing intensity of the phosphorus remain constant ; for the velocity of the cur- 

 I'ent of^air entering the color tube at C for a given jet, varies with the foi-m and 



