32 



Dr. C. A. MacMunn. Researches into the 



from 28 — 32 (or wave-length 568 — 552). So that this solution gives 

 practically the same spectrum as the ethereal and the alcoholic. 



BenzoUc Solution. — Reddish solution giving following spectrum : — 



Extent, 11 to 65 (or wave-length 671—457). 

 Band e, 21 to 23 (or wave-length 604—592). 

 Band B, 28 to 32 (or wave-length 568—552). 

 Band «, 45 to 55 (or wave-length 507 — 480). 



This also gave a band near D when treated with ammonia, which 

 also caused the disappearance of band «. 



At first it seemed possible that the appearance of these bands e and 

 8 might have been due to the action of heat on the pigment during 

 the evaporation, but on evaporating the chloroformic solution under 

 the receiver of the air-pump the same result was arrived at. 



Action of Caustic Soda on Solutions. — If the solutions were examined 

 in a depth sufficient to show band at F distinctly and caustic soda 

 were added, in each case this band disappeared and was replaced by 

 another nearer the red. Thus in ethereal solution the band read 

 42 — 47 (or wave-length 517 — 502) ; and in chloroformic solution the 

 band read 43 — 48 (or wave-length 513 — 499) ; and in alcoholic solu- 

 tion 41-5— 47 (or wave-length 519—502. 



Aqueous Solution. — The aqueous solution gave the black band at F, 

 disappearing with ammonia and moving towards the red with caustic 

 soda. 



Solution of Pigment in Hydro chloric Acid. — It dissolved completely in 

 hydrochloric acid, giving a red solution, which in a sufficient depth 

 showed a band at D, figure (11). 



Extent, 9 to 32 (or wavelength 686—552). 

 Band 7, 20 to 25 (or wave-length 609—582). 



In less depth : — 



Extent, 9 to 63 (or wave-length 686—462). 

 Band «, 45 to 53 (or wave-length 507—485). 



By the ammonia and caustic soda treatment, the spectra were altered 

 in the same manner as those of the other solutions. 



Solution of Pigment in Sulphuric Acid. — A red solution. 



Deep layer : — 



Extent, 8 to 37 (or wave-length 694—534). 

 Band, 21 to 25 (or wave-length 604—582). 



Shallower depth : — 



Extent, 7 to 80 (or wave-length 702—432). 

 Band, 43 to 52 (or wave-length 513—488). 



As all these solutions contained the same pigment, the next step 



