259 



IV. 



Absorption of ultraviolet rays by isatiii and sonie of its 



derivatives. 



AU substances with one exception were studied in alcoholic 

 solutions. 



1) Isatin (Table F. III). 



1.47 gr. were dissolved in 100 cm^ alcohol. This solution 

 bas been diluted furtber in tbe following manner: 

 a., 1 cm^ sol. -)-20 cm^ alcohol. corresponding to 0.00061 gr. in 1 cm^ 

 b., 1 „ „ +30 „ 

 c, 1 „ „ +40 „ 

 d., 1 „ „ +50 „ 



e-> 1 « V +60 „ 



The thickness of the solution layer was in ail cases 19 mm. 



2., Chlo roi satin (Table F. IL) 



0.4536 gr. dissolved in 50 cm. alcohol, and this solution di- 

 luted furthei' as foUows: 



a., 1 cm^ sol. + 10 cm^ alcohol, corresponding to 0.00082 gr. in 1 cm' 

 b., 1 „ „ +15 „ „ „ , 0.00056 „ „ „ 



c, 1 „ „ +20 „ „ „ „ 0.00U43 „ „ „ 



d., 1 „ „ +25 „ „ „ , 0.(.0035 



n 



3., Nitroisatin (Table F. I). 



0. 4810 gr. nitroisatin were dissolved in 25 cm^ alcohol, 1 cm'' 

 of this solution bas been mixed with 60 cm^ of alcohol and 1 cm^ 

 of this solution diluted furtber as follows: 



a., 1 cm^ + 1 cm' alcohol. corresponding to 0.000157 gr. in 1 cm' 

 b., 1 „ + 3 „ „ „ „ 0.0000787 „ „ „ 



c, 1 „ + 7 „ „ , „ 0.0000393 



n n 



d., 1 „ + 15 „ „ „ „ 0.0000197 



4., Meltyli satin (Meltyl-ps-isatin) (Table E. III). 



1.61 gr. were dissolved in 100 cm' alcohol. Furtber dilutions 

 as follows: 



a., 1 cm' + 20 cm' alcohol, corresponding to 0.00077 gr. in 1 cm' 

 b., 1 r + 30 „ „ „ „ 0.00052 „ „ „ 



c-, 1 . + 40 „ „ „ „ 0.00040 „ , „ 



d., 1 „ + 50 „ „ , „ 0.00031 „ „ , 



