422 Dr. Schunck on Rubian and its Products of Decomposition. 



composed with muriatic acid, which leaves undissolved a quantity 

 of red flocks. These, after filtration and washing with water, 

 are dissolved in boiling alcohol. Into the boiling solution is 

 introduced a quantity of hydrated protoxide of tin, which thereby 

 acquires a light brown colour, while the liquid becomes light 

 yellow, and on being filtered boiling hot and allowed to cool, 

 deposits the rubiafine in yellow shining plates and needles, which 

 are purified by recrystallization from alcohol. The oxide of tin- 

 lake left on the filter is treated with cold muriatic acid, which 

 dissolves the greatest part of the oxide of tin, and leaves undis- 

 solved a dark reddish-brown powder. This is placed on a filter, 

 washed first with muriatic acid, then with water, and then treated 

 with boiling alcohol. The alcohol leaves a great part of it un- 

 dissolved, and on being filtered boiling hot deposits on cooling 

 a brown powder consisting of verantine. The liquid on evapora- 

 tion gives a quantity of alizarine, mixed with verantine. The 

 substance left undissolved by the boiling alcohol is dark brown. 

 It is a compound of verantine and oxide of tin, from which I 

 have not been able to extract the oxide of tin by acids or any 

 other means. It is soluble in ammonia and carbonate of soda, 

 and is precipitated unchanged by acids. 



The same products as those just mentioned may be obtained 

 from madder by extracting it with cold or tepid water, allowing 

 the extract to stand until a coagulum has beeen formed in it, 

 placing the coagulum on a calico strainer and then treating it 

 with boiling alcohol. The alcohol leaves undissolved a quantity 

 of ferment, and is found to contain the same substances as those 

 originating from the direct action of the ferment on rubian. 



The liquid filtered from the gelatinous mixture of substances 

 insoluble in water, formed by the action of the ferment, still 

 contains in solution a considerable quantity of sugar. On adding 

 to it a small quantity of caustic baryta, a pinkish- white precipi- 

 tate falls, consisting probably of pectic acid in combination with 

 baryta. The liquid being filtered, the baryta is precipitated 

 with sulphuric acid, the excess of the latter is removed with 

 carbonate of lead, and a small quantity of lead which dissolves 

 is thrown down with sulphuretted hydrogen. The liquid now 

 leaves, on evaporation at the ordinary temperature over sulphuric 

 acid, a brownish-yellow syrup, having the same appearance and 

 properties as the sugar produced by the action of acids on 

 rubian. 



The following analyses prove the identity of the alizarine 

 formed by the fermentation of rubian with that derived from 

 other sources : — 



I. 0*5210 grm. alizarine, produced by the action of the 

 ferment on rubian, lost, on being heated in the water-bath, 

 0-0920 water= 17-65 per cent. 



