RvAN AND O'RiORDAN — Tinctorial Constituents of some Lichens. 95 



in potash to a yellow solution which on heating turned first brownish-red 

 and finally acquired a light brownish-yellow colour. Its alkaline solution 

 decolourised potassium permanganate. The amount of this substance present 

 in the main substance was, however, very small. 



The main constituent, when purified by recrystallization from acetone, 

 forms colourless microscopic needles which on heating begin to turn brown 

 at about 230° C. and become black at about 260° C, without melting. It is 

 insoluble in ether, very slightly soluble in boiling xylene, slightly soluble in 

 alcohol and acetone, and more so in glacial acid. Its alcoholic solution 

 reddens litmus and gives a reddish-violet colouration with a trace of ferric 

 chloride, while with a few drops of the latter it gives a violet-red 

 colouration. It gives no colouration with bleaching powder. The substance 

 itself is coloured reddish-orange by concentrated sulphuric acid, in which it 

 dissolves to an orange-coloured solution. It dissolves readily in caustic 

 alkalis ; it also dissolves in alkaline carbonates and bicarbonates, and in 

 ammonia on warming, the solution in each case being yellow in colour. 

 The solution of the substance in caustic alkali, which is initially of a yellow 

 colour, acquires a reddish-brown tint on standing five or ten minutes, and 

 on heating becomes first very deep red, and then deep brown in colour. On 

 acidifying a concentrated potash solution of the substance with hydro- 

 chloric acid a red or orange-red precipitate is formed ; if, however, the 

 potash solution be first heated until it turns brown and then acidified, a 

 brown precipitate is obtained. 



The substance itself when heated in a test-tube at first turns brown 

 and then black, giving a sublimate on the sides of the tube which appears 

 crystalline on cooling. This sublimate decolourises potassium permanganate 

 in the cold. The solution of the substance itself in potash also readily 

 decolourises permanganate in the cold. 



The purified substance was dried in an air-oven at 100° C, and gave on 

 analysis the following results :— 



(1) 0-1827 substance gave 0-3744 CO, and 0-6580 H,0, corresponding to 



C 55-88, H 3-52 ; 



(2) 0-1601 substance gave 0-3285 CO2 and 0-0548 H^O, corresponding to 



C 55-95, H 3-80. 

 These analyses, for the latter of which we are indebted to Mr. J. Algar, 

 M.Sc, agree well with the formula CsoHoiOis proposed by Hesse (Journ. f. pr. 

 Chem. (2) 63 (1901), pp. 522-553) for salazinic acid, which was found by 

 Zopf in Stereocaulon salazinum (Liebig's Annalen, 295 (1897), p. 222). This 

 formula requires C 56-25, H 3-75. Zopf (Liebig's Annalen, 352 (1907), pp. 

 1-44) proposed for salazinic acid the formula C,sHuOio, which requires C 56-7 



