Diffuse Reflexion of Light on Mail Surfaces. 209 



(7 a) Mean Values of Nos, 5 and 6 for Carbonate 

 of Magnesia. 



e. 



i=0°. 



;=2o°. 



i=40°. 



£=60®. 



«=80°. 



9605 



-50° 











-40 











0427 



-SO 





... 





5782 





-20 





, 





6124 



1227 



-10 







8391 















8135 



6356 



1456 



4-10 





9365 









+20 





9231 



8190 



6149 



1368 



+30 



9375 











+40 



8813 



8289 



7384 



5261 



0675 



+60 



6862 



6366 



5138 



4186 



0854 



+ 80 



2213 



1787 



0818 



0674 



0222 



(8) Plaster of Paris : X = 656 /jl/ul. 



6, 



i=0°. 



i=2Q°. 



i=40°. 



8=60°. 



1=80°. 



-50° 



... 



... 







0346 



-40 











0975 



-30 









6674 





-20 







... 



6901 



1862 



-10 







8773 











... 





8789 



7197 



2133 



+ 10 





9621 









+20 





9366 



8722 



6951 



1954 



+30 



9375 











+40 



8763 



8582 



7708 



6165 



1158 



+60 



6989 



6652 



5880 



4616 



0814 



+80 



2396 



2136 



1262 



1060 



9733 



(9) Plaster of Paris : \ = 492 pp. 



e. 



i=0°. 



e=20°. 



*=40°. 



« = 60°. 



*=80°. 



-50° 











9762 



-40 











0465 



-30 









6165 





-20 









6443 



1441 



-10 







8531 















8676 



6714 



1682 



+ 10 





9317 









+20 





9061 



8354 



6469 



1499 



+30 



9375 











+40 



8709 



8253 



7518 



5632 



0611 



+ 60 



6857 



6610 



5820 



3956 



0076 



+80 



2290 



1833 



1150 



0481 



9000 



Phil. Mag. S. 5. Vol. 49. No. 297. Feb. 1900. 



