OF SULPHURIC ACID UPON VARIOUS CLASSES OF VEGETABLES. 
475 
the crude fucusine with the acid mother-liquors out of which the crystals of nitrate 
bad been deposited, successive crops of crystals may be readily obtained. These are 
still further purified by being repeatedly crystallized out of hot water, and they may 
be easily obtained in large shining rhombic prisms when deposited from an alcoholic 
solution. By dissolving the colourless crystals of pure nitrate of fucusine in water, 
and slightly supersaturating the solution with ammonia, fucusine gradually subsides 
in white, short flattish prisms forming small stars. 
When pure fucusine is dissolved in boiling water, the solution, so soon as it begins 
to cool, grows turbid, and in the course of a few hours the fucusine is deposited in 
short flattish prisms arranged in fan-shaped figures on the sides and bottom of the 
vessel. Its mode of crystallizing strongly contrasts with that of furfurine, which, so 
soon as its solution begins to cool, forms long slender needles which in a short time 
fill the whole of the liquid. Furfurine may be obtained from pure furfuramide with 
little more than a trace of adhering resin, but even from nearly colourless fucusamide 
I was seldom able to procure much more than two-thirds of fucusine, the remainder 
being changed into a dark -coloured tenacious resin. 
The cold aqueous solution of fucusine is distinctly alkaline to test-paper, and its 
alcoholic solution, as might have been expected, is still more strongly so. Fucusine 
and furfurine are nearly equally soluble in boiling water, but fucusine dissolves in 
2'400 parts by weight of water at 8° C., while furfurine requires 4'800, or exactly twice 
the quantity at the same temperature. This is one reason that while a hot aqueous 
solution of furfurine, on cooling, is filled with long slender crystals of that base, a 
much smaller portion of fucusine crystallizes out, as twice as much of it is retained 
in the cold solution. Fucusine is however considerably less soluble in dilute spirits, 
at ordinary temperatures, than furfurine. 
1. 0'393grm. fucusine dried in vacuo, gave 0’97 carbonic acid and 0'162 water. 
II. 0‘457 grin, fucusine dried in vacuo, gave by Will’s process 0‘75 arnmonio-chlo- 
ride of platinum= 10‘30 nitrogen. 
Calculated numbers. 
30 C 2250-0 
67-17 
Found numbers 
67-30 
12 H 
149-7 
4-47 
4-58 
2 N 
350-4 
10-45 
10-30 
6 O 
600-0 
17-91 
17-82 
3350-0 
100-00 
100-00 
It is plain from the result of this analysis, that fucusine and furfurine are also iso- 
meric compounds. 
Nitrate of Fucusine. 
This is one of the salts of fucusine which crystallizes most readily. I have already 
detailed the mode of preparing and purifying it, and shall not therefore repeat it again. 
When crystallized out of a hot aqueous solution, it forms long prisms tapering towards 
their extremities, and united by their broad ends so as to form large stars. But when 
crystallized out of spirits of wine, it forms large rhombic prisms of great regularity of 
structure and adamantine lustre. When deposited from strong spirits of wine, these 
3 p 2 
