OF SULPHURIC ACID UPON VARIOUS CLASSES OF VEGETABLES. 
479 
plants, as it yields an identical product of decomposition, viz. furfurol when it is di- 
gested with sulphuric or muriatic acids. 
Thematiere incrustafitem Fuci,on the other hand, though analogous, appears to be 
not identical with the corresponding principle in phanerogamous plants, as it yields 
fucusol instead of furfurol ; and this seems also to be the case with the matiere incrus- 
tante of mosses and lichens, both of which families approximate much more closely in 
their botanical structure to the Algse than to ordinary phanerogamous plants. As 
might almost have been expected, therefore, both mosses and lichens appear to yield 
fucusol, or at any rate an exceedingly similar oil, which is certainly not furfurol. 
Ferns, on the contrary, whose woody structure differs from that of either mosses, algae, 
or lichens, and approaches pretty closely to that of ordinary phanerogamous plants, 
appear to yield an oil with properties intermediate between those of furfurol and 
fucusol. 
Note received September 4, 1850, from Professor Miller of Cambridge. 
I consider it very probable that the crystals of nitrate of fucusine do not belong to 
the prismatic system, but are twin crystals of the oblique system. The faces of the 
form s are however too imperfect to settle this point. 
The angles between normals to the faces are, — 
O / 
ma 47 52 
mm! 84 16 
I have re-examined the crystals with all possible care, but cannot pretend to correct 
the angles which the faees of the forms s,u make with each other, and with the faces 
of the forms a, m. 
Corrected angles between the normals to the faces of nitrate of furfurine {not from 
solution in alcohol) are, — 
O t 
ea 
71 
5 
ee' 
37 
50 
nh 
47 
54 
tb 
65 
41 
ab 
90 
0 
nri 
84 
12 
tt' 
48 
18 
sa 
72 
44 
ss' 
34 
32 
sb 
66 
16 
ss" 
47 
28 
s's" 
60 
0 
The values of the angles between the faces of the form s are very uncertain. 
