PROXIMATE PRINCIPLES OF SOME OF THE LICHENS. 
77 
Pyramidal .... 1 1 1, 1 1 1 =38° 58' 
Simple forms a 100, rill 
^ 311. 
The form to which the faces s belong is usually 
hemihedral with parallel faces, 11 313. In two 
crystals only, out of ten which were examined, 
faint indications of the faces of the other half 
form were observed. 
The angles between normals to the faces are, — 
aa' 90 6 
ra 70 31 
sa 43 18 
r/-' 38 58 
rr, 56 17 
.svy, 100 12 
No cleavage observable. 
The index of refraction, for the brightest part of the spectrum, of the ordinary ray 
= 1*545 ; of a ray in a plane perpendicular to the faces a, a!, polarized in that plane 
= 1*523. 
Pseudo-orcin is quite neutral to test paper. It has a very sweet taste, though 
scarcely so sweet as that of orcin. When heated on platinum foil it burns with a 
blue flame, and emits a smell similar to caramel. When distilled it yields a thin 
yellowish liquid, emitting at the same time the smell of burnt sugar. The liquid is 
soluble both in water and in alcohol ; it does not crystallize on standing. 
Ammonia and hypochlorite of lime have no action upon pseudo-orcin; neither is 
it affected by any of the alkalies. It is not acted on by bromine. It is not affected 
by cold nitric acid, but hot nitric acid converts it into oxalic acid. It is not blackened 
by cold sulphuric acid, but when heated with that acid it becomes brown. Pseudo- 
orcin gives no precipitate with neutral or basic acetate of lead, with nitrate or am- 
rnonio-nitrate of silver, or with salts of copper. It is incapable of fermentation. 
Dried in vacuo, and then at 212° Fahr., it lost no water. 
I. 0*507 grm. dried at 212° Fahr., gave with chromate of lead 0*734 C 02 and 0*3813 
water. 
II. 0*6275 grm. dried at 212° Fahr., gave 0*907 C 02 and 0*467 water. 
III. 0*4702 grm. dried at 212° Fahr., gave 0*679 C 02 and 0*355 water. 
Calculated numbers. 
I. 
II. 
HI. 
IOC 764*3500 
39*67 
39*46 
39*42 
39*36 
13 H 162*2335 
8*42 
8*55 
8*30 
8 60 
10 0 1000*0000 
51*91 
51*99 
52*28 
52*04 
1926*5835 
100*00 
100*00 
100*00 
100*00 
Fig. 1. Fig. 2. 
