348 On the Purification of Mercury. 
Description of the Plate. 
Fig. 1. is the germ of a gourd when the flower and seed- 
vessels ay first béginning to form. 
Fig. 2 is the mechanism belonging to every single seed or 
grain af w heat, and intended to furnish nutriment to the seed 
both from the “earth and atmosphere: but this curious display 
belongs to the atmosphere principally. (@) is the heart of the 
grain’ when it first enters the almost empty bag of the seed @, , 0, 
which is now only inflated with air. The feather oo conveys 
the pollen to fructify the seed, and then takes with the hairs b66 
the nutriment from the atmosphere, while the vessels d dd after- 
wards supply the powdered nutrimeut from the root. 
Fig. 8. is a specimen of the gourd (before the flower passes 
off) cut horizontally, to show how the nutriment is principally 
taken in from the root and pours up the vessels (formed for the 
time) in the pith, and thrown into the seed-vessels by means of 
the pipes ce c, which are seen to give a fine powder, and thus 
fill each seet-vessel:—cut them which way you will, they equally 
yield the same picture. 
Fig. 5. is the natural size of the wheat seed, when beginning : it 
is of no use to try it when older, the process is then over :—when 
once the seed is ready for the earth, a new process begins: all 
then is forming for the new embryo, which i is indeed even at this 
time preparing in the heart of the seed. But I thought it would 
make a confusion to show its curious mechanism here. 
Fig. 1. shows the gourd cut perpendicularly, with the seeds 
properly placed, receiving the juices of the atmosphere. 
t 
a a ee ee ea 
LVI. “Della Purificaxtone del Mercurio Memoria del Sig. Dott. 
G.Brancui,” &c.— Memoir on the Purification of Mercury. 
by Dr. Josxrn Brancut, Public Professor of Chemistry in 
the University of Pisa, Corresponding Member of the Royal 
Academy of Science of Pistoja, &c.* 
Tue mercury of commerce is generally in a state unfit for ex- 
periments in chemistry or physics, in consequence of being mixed 
with various metals, particularly lead and bismuth. Jn this state 
of adulteration its lustre soon tarnishes; it weighs lighter than 
when pure ; leaves a blackish spot when poured on an earthen 
plate ; divides into drops which though roundish are generally 
more or less compressed, and have an appendage or kind of tail; 
and on being exposed to the action of the fire immediately aban- 
dons the metals with which it was amalgamated. 
Distillation is the known and generally-practised method of 
* From the forthcoming Memoirs of the Pisa Academy- 
purifying 
