PROXIMATE PRINCIPLES OF SOME OF THE LICHENS. 
401 
I. 0*3755 grm. quintonitrated-erythromannite, dried in vacuo and burned with 
chromate of lead, gave 0*228 carbonic acid and 0*083 water. 
II. 0*394 grm. quintonitrated-erythromannite, dried in vacuo and burned with 
chromate of lead, gave 0*241 carbonic acid and 0*089 water. 
10 tubes gave 329 measures of mixed gases consisting of 227 carbonic acid and 
102 measures nitrogen, or carbonic acid gas in the proportion of eleven to five 
nitrogen. 
Quintonitrated-erythromannite. Found. Quintonitrated-mannite. 
Calculated numbers. 
per cent. 
I. 
11. 
Calculated numbers. 
per cent. 
lie 825 
16*75 
16*56 
16*68 
12 c 900*0 
17-66 
9H 112 
2*27 
2*46 
2*50 
9H 112*3 
2*21 
5N 885 
17-98 
17*83 
17-83 
5N 885*0 
17-36 
31 0 3100 
63*00 
63*15 
62*99 
32 0 3200*0 
62*77 
4922 
100*00 
100*00 
100*00 
5097-3 
100*00 
The rational formula of quintonitrated-erythromannite is therefore Hy Og 
-f-5N05 = erythromannite, in which five equivalents of water are replaced by five 
equivalents of nitric acid, and corresponding exactly in this respect with quinto- 
nitrated-mannite, in which five equivalents of water are also replaced by five equi- 
valents of nitric acid. I conclude by subjoining the formulae of these four com- 
pounds, which only differ from each other by one equivalent of carbonic oxide, that 
so their mutual relations may be seen at a glance. 
Mannite .... 0^2 H14 Oi2. Quintonitrated-mannite .... Hg O7-I-5NO5. 
Erythromannite C44 H14 O44. Quintonitrated-erythromannite C14 Hy Og-j-fiNOg. 
Glasgow, \2th February 1849. 
