6 Dr. J. Stenhouse on Alpha- and Beta-Orcine. 



When usnic acid is boiled with lime or baryta, the excess of 

 base is removed by a current of carbonic acid gas, and the 

 clear liquor evaporated to dryness on the water-bath. The 

 dried mass is then to be agitated with aether; and on the eva- 

 poration of the aether, the beta-orcine is deposited in nearly 

 colourless crystals. 



Beta-orcine is tolerably soluble in cold water, though not 

 nearly so much so as alpha-orcine, but very soluble in boiling 

 water. It is very soluble in alcohol and in aether. It has a 

 faint but distinctly sweetish taste. It has no reaction upon 

 test-paper, and is a perfectly neutral body. When heated, it 

 sublimes without leaving any residue. The smell of its vapours 

 is suffocating. It inflames readily, and burns with a strong 

 smoky flame. 



In the course of a few minutes it assumes, with ammonia, 

 a beautiful blood-red colour, which on standing becomes 

 deeper. Beta-orcine is much more rapidly acted on by am- 

 monia than alpha-orcine. The colour which alpha-orcine 

 yields with ammonia is reddish-brown. When left in contact 

 with caustic or carbonate of potash, beta-orcine yields a beau- 

 tiful reddish-purple dye stuff. This appears to be the same 

 amorphous red body which Knop observed when preparing 

 usnate of potash, without, however, his remarking the source 

 which produced it. The smallest portion of beta-orcine in- 

 stantly strikes a bright blood-red colour, with a solution of 

 hypochlorite of lime; just as alpha- and beta-orsellic and ery- 

 thric acids do with the same reagent. Alpha-orcine, on the 

 other hand, yields a purple violet colour with hypochlorite of 

 lime. 



The crystals of beta-orcine, when dried in the air and then 

 in vacuo over sulphuric acid, do not lose any water. The four 

 following analyses were made with beta-orcine prepared on 

 four different occasions: they were all dried in vacuo: — 



I. 0*3 17 grm. orcine burnt with chromate of lead, gave 

 0-8002 CO 2 and 0-209 water. 



II. 0-391 grm. orcine burnt with chromate of lead, gave 

 0-985 CO 2 and 0-254 water. 



III. 0-2608 grm. orcine burnt with chromate of lead, gave 

 0-657 CO 2 and 0-173 water. 



IV. 0-3138 grm. orcine burnt with chromate of lead, gave 

 0-800 CO 2 and 0*212 water. 



Calculated numbers. I. II. III. IV. 



38 C 2904*530 69-08 68*84 68*70 68-70 69*20 



24. H 299*508 7*12 7*32 7*22 7*36 7*50 



10 O 1000-000 23*80 23*84 24'08 23'94 23*30 



4204*038 100*00 100-00 10000 lOO'OO 10000 



