Dr. Schunck on Ruhian audits Products of Decomposition. 433 



consist of small crystalline needles grouped round a centre. 

 Occasionally it has an orange tinge, but this is probably due to 

 some impurity. When heated on platinum foil, it melts to a 

 brownish-red liquid and then burns with flame, leaving a large 

 quantity of carbonaceous residue which burns away with diffi- 

 culty. When heated in a tube, it gives a small quantity of 

 crystalline sublimate mixed with oily drops. When slowly 

 heated between two watch-glasses, it melts to a brownish-red 

 mass, but gives no sublimate. It is quite insoluble in boiling 

 water, to which it hardly communicates a tinge of colour. It 

 is more easily soluble in boiling alcohol than rubianine or even 

 rubiadine, and does not crystallize out on the solution cooling, 

 but is left, on evaporation of the alcohol, in crystalline masses 

 as just described. It is soluble in concentrated sulphuric acid 

 with a dark reddish-brown colour ; the solution, on being heated, 

 disengages sulphurous acid and becomes black. Boiling nitric 

 acid dissolves it with a disengagement of nitrous acid to a yellow 

 liquid, while some oily drops rise to the surface. On the solu- 

 tion cooling, a quantity of light yellow crystals, possessed of 

 much lustre, are deposited. Whether these crystals are a 

 product of decomposition, or whether they are the substance 

 itself in a state of purity, the impurities having been destroyed 

 by the nitric acid, I am unable to state. The latter is the more 

 probable view. Rubiagine is soluble in boiling acetic acid with 

 a yellow colour, and crystallizes out again, on the solution cooling, 

 in small needles. Ammonia turns it red, and on boiling dis- 

 solves it with some difficulty, forming a blood-red solution, which 

 on evaporation loses its ammonia and leaves the substance behind 

 in the shape of small yellow crystals. It dissolves more easily 

 in caustic soda, with the same colour. It is precipitated from 

 its alkaline solution by acids in lemon- yellow flocks. The ammo- 

 niacal solution gives very slight precipitates with the chlorides 

 of barium and calcium, the solution remaining red with chloride 

 of barium, and becoming crimson with chloride of calcium. It 

 is soluble in baryta and lime-water with a blood- red colour, and 

 is reprecipitated by a current of carbonic acid. The alcoholic 

 solution gives, on the addition of acetate of lead, at first no pre- 

 cipitate, but the colour of the solution becomes dark yellow, and 

 after some time, provided the solution be not too dilute, an 

 orange-coloured granular precipitate falls, which is the lead com- 

 pound of rubiagine. If no deposit is formed, then the addition 

 of water causes an orange-coloured flocculent precipitate, which, 

 after being separated by filtration and washed with water in 

 order to remove the acetate of lead, is found to be very little 

 soluble in boiling alcohol, but is easily soluble in a boiling alco- 

 holic solution of acetate of lead with a dark yellow or orange 



