Diffuse Reflexion of Light on Matt Surfaces. 213 



those which would have to be added to log cos i (Lambert) in 

 order to give the real results. 











In the 



mean 



i. 



English 

 red. 



Chroniate 

 of potash. 



Zinc 

 green. 







Carbonate 



of 

 magnesia. 



Plaster 



of 

 Paris. 



i= 0° 6=30° 



0000 



OUOO 



0000 



0000 



0000 



/ = 20 e=10 



+0071 



-0063 



-0552 



-0298 



-0194 



*' = 40 e= 



-0004 



+ 0100 



-0130 



-0407 



-0110 



i = 60 *.= 



+0305 



4-0223 



-0031 



-0633 



-0034 



e'=80 e = 



+0582 



+0327 



-0133 



-0940 



-0489 



Ergo : 



9' = 0240 



9' =0193 



9=0211 



9' =0569 



9 ' = 0207 



2. Deviations from the Law of Emission. — The figures 

 would have to be added to lo^' cos e (Lambert) to give the 

 real results. 





English 



Chr ornate 



Zinc 



In the 



mean 



• 



, 







red. 



of potash. 



green. 



Carbonate 



of 

 magnesia. 



Plaster 



of 

 Paris. 



*= 0° 



0050 



0056 



0010 



0113 



0075 



?'=20 



C037 



0059 



0077 



0046 



0062 



? = 40 



0298 



0017 



0236 



C040 



0081 



*=60 



0032 * 



0213 * 



0020 * 



0064 * 



0063* 



\ £=80 



0057 * 



0179 * 



0233 * 



0280 * s 



0112* 





9"=0C95 



9"=0105 



9"=0115 



9" =0109 



9" =0079 



* 6 = 60° and e = 80° is omitted in the calculation of 9". 



3. Deviation from Lamberts law in totality : 



Carbonate of magnesia. Plaster of Paris. 



English Chroniate Zinc s * ~v * — > 



red. of potash. green. Bed part of Blue part of Bed par', of Blue part of 



spectrum. spectrum. spectrum. spectrum. 



9=0223 9=0245 9=0255 9=0282 9 = 0554 9=0132 9 = 0254 



0043 unit of Brigg's logarithms being 1 per cent, of the 



