326 Mr Filon, On the variation with the wave-length 



Fig. 3. Glass 103. 



'X-5400\ , . Aooc/ <-i00 \ 



iJ ; (; i^J + - 0236 v-Too(r;- 



(7 = 2-83 --0825 



A - 5400\ 



O ill 



Wave-lengths in tenth-metres. 



x Observations A.) 



+ „ B. - Table IV. 



O ,. o.| 



