PROXIMATE PRINCIPLES OF SOME OF THE LICHENS. 
65 
pretty soluble in cold alcohol and ether, and very readily so in boiling alcohol. Its 
solutions redden litmus paper very distinctly, and it neutralizes the alkalies and 
alkaline earths, forming soluble and crystal lizable salts. Its most characteristic 
reaction, by which its presence can be very readily detected, is the deep blood-red 
colour it instantly strikes when it is brought in contact with a solution of hypochlo- 
rite of lime. The red colour only remains for a minute or two, and then changes to 
a deep yellow, which also gradually disappears. This is a property which orsellic 
acid possesses in common with most of the red colouring principles of the lichens 
with which we are acquainted. The orsellic acid is rapidly oxidized by contact with 
the hypochlorite of lime, and is converted into a dark green uncrystallizable resin. 
This reaction of hypochlorite of lime on these colouring principles forms a very 
beautiful class experiment. It may be readily shown by pouring a weak solution of 
bleaching powder into a basin containing either an alkaline or an alcoholic solution 
of the lichen, or perhaps best of all, simply on the gelatinous precipitate itself. The 
only precaution to be observed is that no free acid be present. A solution of orsellic 
acid in ammonia on exposure to the air soon assumes a bright red colour, which 
gradually becomes darker and more purple-coloured on standing. When heated on 
platinum foil, it burns with a yellowish flame, leaving no residue ; when it is distilled, 
it yields a little empyreumatic oil and orcin. 
Orsellic acid gives a copious white precipitate with ammonio-nitrate of silver, 
which however is soon decomposed. It is also precipitated by basic, but not by 
neutral acetate of lead. 
I. 0*216 grin, acid dried at 212° Fahr. and burned with chromate of lead, gave 
0*475 carbonic acid and 0*098 water. 
II. 0*233 grm. acid gave 0*521 carbonic acid and 0*105 water. 
III. 0*3033 grm. acid gave 0*676 carbonic acid and 0*1361 water. 
Calculated numbers. 
32 C 2445*920 60*46 
16 H 199*672 4*93 
14 O 1400*000 34*61 
4045*592 100*00 
I. 
II. 
III. 
60*00 
60*98 
60*78 
5*03 
5*00 
4*98 
34*97 
34*02 
34*24 
100*00 
100*00 
100*00 
These analyses give C 32 H 15 Ojg-i-HO for the rational formula of hydrated alpha- 
orsellic acid. 
The Baryta Salt. 
In order to form the baryta salt, pure orsellic acid was dissolved in a slight excess 
of cold baryta water, and a current of carbonic acid gas was passed through the 
solution till all excess of baryta was removed. The precipitate, which consisted of 
carbonate of baryta and the organic acid, was collected on a filter and dried. It was 
then treated with hot alcohol, which dissolved out the salt and deposited it on cooling 
in small shining crystals arranged in stars. 
MDCCCXLVIII. K 
