164 Professor Haussmann on Metallurgic Crystallography , 
scoriae which cover the surface of the iron, in crystals about the 
size of half an inch. In a perfect specimen of these crystals, 
there are very thin hexangular plates, which may be cut in the 
direction of the terminating planes into thinner plates, possess- 
ing a mixed lustre, but no transparency. On the edges of the 
crystals we observe very small planes, inclined towards the ter- 
minal planes at oblique angles, from which it may be conjec- 
tured, that the hexangular plates are the segments of a funda- 
mental rhomboidal form. 
Native foliated graphite, which occurs in its most perfect state 
in Greenland, at times exhibits specimens of crystallisation simi- 
lar to those of artificial graphite, though rarely in so complete a 
form. 
( To be continued.) 
Art. XXV. — On a Remarkable Plant of the Order Fungi , 
found growing in a Solution of Succinate of Ammonia, (with a 
Figure.) By John Fleming, D. D. F. R. S. E. & M. W. S. 
TChe well-known circumstance, that many kinds of fungi make 
their appearance in a state of healthy vegetation, whenever 
there is a soil adapted for their growth, without our aid, or the 
assistance of any visible means, has excited surprise in the minds 
of the most superficial observers, and bewildered philosophers 
in their attempts to account for the phenomena of nature. The 
droppings of corn-fed horses, placed in layers with common 
earth, will, in the course of a short time, produce a plentiful 
crop of the common eatable mushroom. Corrupting vegetable 
or animal matters speedily exhibit a hoary covering of mucor. 
These different kinds of plants vegetate, and go through all the 
stages of their existence, whether the soil in which thev germi- 
nate be exposed to day, or lodged in darkness. Whence it 
may be asked, do they derive their origin ? 
The doctrines of equivocal generation offered an easy solu- 
tion of this question. The supporters of these were disposed to 
consider chance as bringing together the particles necessary to 
constitute the germs of the plant, and the soil as supplying the 
future requisites of its growth and maturity. The total over- 
