136 Intelligence and Miscellaneous Articles, 



bleaches with water. The alcoholic solution is decomposed by wa- 

 ter; it then has a pale yellow milky appearance, which it is difficult 

 to render clear, and it retains this appearance after the evaporation 

 of the alcohol. By spontaneous evaporation it separates from the 

 alcohol in the state of a granular crystalline mass, ^ther dissolves 

 it in large quantity, and it remains, after the evaporation, transpa- 

 rent and of a yellow colour. When mixed with sulphuric acid it 

 becomes brown; a small quantity, altered in properties, is dissolved; 

 the solution is yellowish brown, and is precipitated by water of 

 greyish white. By caustic potash it is but very slightly dissolved, 

 and the solution when exposed to air and light becomes colourless; 

 acids throw down pale yellow flocks from the potash, which when 

 properly washed do not redden litmus. It is but little, if at all so- 

 luble in carbonate of potash, and is insoluble in caustic ammonia, 

 to which, however, it imparts a yellow colour. This yellow colour- 

 ing matter is then a peculiar fatty matter, intermediate as to the fat 

 oils and the resins, which may be bleached and retain its property 

 of dissolving in alcohol with difficulty. It may be called Xantho- 

 phylle (from lavQos^ yellow, and ^vWov, foliage). Berzelius thinks 

 that there is every reason to suppose, that during the disappearance 

 of the green colour of leaves, and its conversion to a yellow colour, 

 this is derived from the green, by means of some change in the or- 

 ganization of the leaf, effected by cold, which modifies the organic 

 action ; he tried in vain to reproduce the green colour from the 

 yellow, nor could he convert the green to yellow. There is nothing 

 in common between the brown and the yellow colour of the foliage; 

 the former is produced by an extractive principle which is at first 

 colourless, and which after the disorganization of the epidermis of 

 the foliage, becomes brown by the action of oxygen ; it then com- 

 municates to the fibre of the skeleton of the foliage a brown colour, 

 which cannot be removed even by digestion in caustic potash, nor 

 destroyed by long treatment with sulphuretted hydrogen. — Journal 

 de Pharmacies July 1837. 



DETECTION OF METALLIC CHLORIDES IN BROMIDES AND 

 IODIDES. BY M. HENRY ROSE. 



It is very easy to discover small quantities of soluble bromides 

 and iodides in great quantities of metallic chlorides ; but on the 

 contrary, it is very difficult to discover minute quantities of metallic 

 chlorides in large quantities of metallic bromides and iodides. 



After many experiments, M. Rose succeeded in discovering very 

 small quantities of chloride in bromide of sodium; when bromide of 

 sodium is mixed with excess of chromate of potash, and the mixture 

 is distilled with concentrated sulphuric acid, pure bromine only is 

 given out, which dissolves in excess of ammonia, forming a solu- 

 tion which is perfectly colourless. If chloride of sodium be treated 

 in the same manner, there is obtained chromate of chloride of chro- 

 mium, the colour of which very much resembles that of pure bro- 

 mine, but which, when dissolved in ammonia, forms a solution of a 

 deep yellow colour, in which the usual tests easily discover the pre- 

 sence of chromic acid. 



