CHLOROPHYLL AND THE CHLOROPLASTS 347 



absorption spectra of the various components. The absorption of chloro- 

 phyll in the infra-red and ultra-violet has been studied by Van Gulik ^^ 

 and in the latter region also by Marchlew^ski and Moroz.^" 



In the publication of Willstatter and StoU are reproduced the spectro- 

 graphs of chlorophyll solutions of various concentrations. Chlorophyll a 

 has seven sharply defined absorption bands in the visible portion of the 

 spectrum and the end absorption in the violet. The strongest absorp- 

 tion is evidenced by one band in the red, one in the indigo-blue and one 

 in the violet portion ; the w^eakest absorption bands are in the yellow 

 and green. The follow^ing absorptions are given by Willstatter and Stoll 

 for 0.0431 gram of chlorophyll a in 1000 cc. of ether (0.001 mole in 20 

 liters). 



-Thickness of Layer in mm. 



2.5 10 40 80 



Band I 669 655 675—648 680— 637. 625\ ^...rQA ?87 



" II 619 1605 623.. 603 625 600 / o»'*— ^^^-^^^ 



" III — 585.570 586... 564 587—561 



" IV — — 539. .523 541. ..521 



"V — — 504 1489 504.488 



" VI 462 1455 465.453 



VII \ 439-427 \ 444_ \ ^^1 -^ [ 473- 



End absorption VIII. i ...415— / ^^^^ J ^°^ J 



The absorption spectrum of chlorophyll h has nine bands between 

 "k = 700 and 410 |i^i and the end absorption beginning at 400 \iyi. The 

 intensity of these bands diminishes in the following order: VIII, II, IX, 

 X, I, IV, III, V, VII. 



The following absorption bands are given by Willstatter and Stoll for 

 0.0431 gram of chlorophyll b in 1000 cc. of ether: 



, Thickness of Layer in mm ^ 



2.5 10 40 80 



673—625 1 677—582. . 



574... 559 



Band I 666 . 659 667. . .659.651 



" II 648... 638 651—635 



"III — 615 I 611 615.609 



" IV — 599.585 600... 583 



"V — — 571 559 



" VI — — 547. .530 549... 530 



"VII — — 506 I 500 



" VIII 467—446 1 1 ] 



" IX 433.-424 ^474— M83— i 508.489 



End absorption X.... 407— J J J 



Warburg and Negelein ^* also determined the coefficient of absorption 

 of a solution of an extract of all the leaf pigments obtained from 

 Chlorella according to the method of Willstatter. A methyl alcohol solu- 

 tion thus showed lowest absorption in the green (546 [.i|.i), 1.8 times this 



"Van Gulik, Ann. Phxsik. (4), 23, 277 (1907)7 46, 147 (1915). Eckerson, 

 Bot. Gaz., 40, 302 (1905). 



"Marchlewski and Moroz, Bull. soc. cliini., 35, 705 (1924). Ursprung, Bcr. bot. 

 Ges., 36, 73 (1918). 



"Warburg and Negelein, Zeit. physik. Chan., 106, 195 (1923). 



