252 Mr Purvis, The influence of dilution on the colour 



5 solution ; band 2 had decreased in width very considerably 

 in the 310 solutions ; band 3 was also not so wide in the 310 

 solutions, but the difiference was not so striking as in band 2 ; 

 and bands 4 and 5 have very slightly increased in width in the 

 310 solutions. 



Besides these changes, there was more general absorption in 

 the 310 solutions, but the increase since the observations of two 

 days ago was not very great. 



Also, the shift of the bands towards the red end as noticed in 

 E was similarly marked. 



J. The solutions stood for three weeks longer in the dark and 

 they were again examined. 



Barium permanganate 1 , c ^ i j.- 

 -T) , ■ ^ 1° ^ 154 solutions, 



rotassmm do. J 



do. do. 5 solutions. 



The 154 barium permanganate solution was of a purplish 

 colour, and there was a slight opalescence ; the 154 potassium per- 

 manganate solution was rose pink coloured and perfectly clear. 



In the 154 barium permanganate solution the bands 1, 2 and 

 3 were again narrower than the corresponding bands in the 

 5 solution ; whilst bands 4 and 5 were slightly wider, and general 

 absorption was more pronounced in the 154 solutions than in 

 the 5 solution. Similar remarks apply to the 154 potassium 

 permanganate solution. 



K. Barium permanganate | ^i a i j.- 

 Potassium do. J 



do. do. 5 solutions. 



These solutions were perfectly clear, and showed no opalescence. 

 The colours of the 310 solutions were brownish yellow. 



The 5 barium permanganate solution showed the bands well 

 marked, and very little increase in the general absorption from 

 the earlier observations — the bands 1, 2 and 3 were very faint 

 and narrow in the 310 solutions, and just beyond this towards the 

 ultra violet there was complete general absorption. 



In the 310 potassium permanganate solution the bands 1, 

 2 and 3 were faint but they were better marked, and bands 4 

 and 5 were only just visible, but they were wider, than the 

 corresponding bands in the 5 solution. Just beyond band 5 on 

 the more refrangible side there was complete general absorption 

 in the 310 solutions. 



So that these experiments .prove that the changes of the 

 solutions made in the dark and kept from the influence of light 

 were very similar to those which had been subjected to the action 

 of light ; although light appeared to accelerate the rapidity of the 

 changes. 



