Intelligence and Miscellaneous Articles. 135 



oxygenated bodies; it is nitrous acid, in which oxygen is replaced by 

 sulphur. Sulphuret of azote possesses the general character of the 

 amides ; by combining with water it changes into ammonia and an 

 acid. — L'Institut,'biov.}831. 



XANTHOPHYLLE, — THE COLOURING MATTER OF LEAVES IN 

 AinUMN. 



Berzelius immersed the lemon-yellow autumnal leaves of ihePi/rns 

 communis, immediately after they were gathered, in alcohol of sp. 

 gr. 0*833, and they remained in it for 48 hours. The alcohol be- 

 came of a yellow colour, but the leaves were slill yellow, though 

 paler than at first. The alcohol was decanted, and the bottle was 

 kept for some time inverted : the leaves, whenever they were acted 

 upon by the air, became brown, whereas the parts of the leaves in 

 contact with the bottle retained their yellow colour. Alcohol was 

 repeatedly poured upon the leaves, and was each time rendered 

 yellow ; and lastly, the leaves were boiled in alcohol : it still ac- 

 quired a slight yellow tint, but became gelatinous on cooling. The 

 various alcoholic solutions were mixed and distilled to l-8th ; there 

 was then deposited agranular and somewhat crystalline substance; 

 after this was separated, the distillation was continued, until there 

 remained only the water of the vegetation of the leaves. On this 

 yellowish brown liquor there floated a soft, yellow, greasy sub- 

 stance, which appeared identical with the grains containing the yel- 

 low colouring matter of the leaves. These grains do not appear 

 when examined by the microscope to possess any crystalline struc- 

 ture; when rubbed by the hnger they become a yellow unctuous 

 greasy matter; this is mixed with a small quantity of fat oil, which 

 could not be separated with any certainty, with another greasy sub- 

 stance also ; the greater portion of tiie former may be separated 

 by digestion with potash, which saponifies the oil and dissolves but 

 little of the yellow grease ; the yellow fat acids are precipitated 

 from the alkaline solution by hydrochloric acid ; and by redissolvir.g 

 them in water containing in each ounce about five or six drops of 

 ammonia, and again precipitating, they may be obtained colourless. 

 In order to deprive it of the solid fatty matter, it must be treated 

 with cold alcohol, in which it is not soluble. It was not possible to 

 separate these two fatty matters. As it was procured it was a yel- 

 low unctuous fat, readily fusible and liquefying at 108°Fahr. j 

 it then concretes, becomes transparent and yellowish brown ; 

 it cannot be volatilized without decomposition, and when distilled it 

 yields a brownish fat, which is slightly soluble in alcohol, and leaves 

 a residue of carbon. It is insoluble in water, but if when melted, hot 

 water be poured upon it, it becomes transparent, swells slightly, 

 assumes a paler yellow colour, as if water had chemically combined 

 with it. When sprinkled with water and exposed for a long time 

 to the air and light it becomes colourless, and a fatty mutter is 

 formed which is with difficulty soluble in alcohol, and when dissolved 

 in it by heat it precipitates light white flocks as the solution cools. 

 The yellow fat is also but slightly soluble in alcohol. It does not 

 sensibly become colourless in the solution, in the same time that it 



