214 State of Chemical Science on the Continent. 
Among the printed papers sent in to the Society were : 
A paper by M. Lasteyrie, on making flour and bread from 
potatoes; by which it appears that this vegetable may be kept 
for many years in the state of powder. 
A paper by Baron de Werneck, showing the quantity of po- 
tash contained in the various trees, shrubs, and plants, which 
yield this substance. 
XLIX. Intelligence and Miscelianeous Articles. 
STATE OF CHEMICAL SCIENCE ON THE CONTINENT. 
Extract of a Letter from M. DopErEtner io M.Van Mons*. 
Jena, 23d February. 
Ix a note to p. 59 of my Elements of Pharmaceutical Che- 
mistry, I expressed a suspicion that phosphorus might be com- 
posed of a peculiar substance and of hydrogen. This idea, which 
was founded upon a particular experiment, has since been ccn- 
firmed. . 
If we introduce into a retort three parts of iodine and one of 
phosphorus, both as dry as possible, and heat them by the flame 
of a spirit lamp, the two bodies will penetrate with an extrica- 
tion of light and vaporisation of hydro-iodic acid, and there will 
remain in the retort a brilliant substance of a brownish-red co- 
lour, which, when washed and dried, keeps in the air without 
being altered at the habitual temperature of that fluid: by a 
strong heat, however, it inflames and burns in the air, dries, 
and forms vapour of phosphoric acid. As the hydro-iodic acid 
is the product of the combination of hydrogen with iodine, and 
as the latter no more than phosphorus contains water, we ought 
to admit that the hydrogen has taken its origin from the phos- 
phorus, and that the reddish-brown residue, after being washed 
and dried, is de-hydrogenated phosphorus. This conclusion is 
also confirmed by the circumstance, that the new iodine, heated 
with the residue, gives no Jonger hydro-iodic acid. According to 
this result, phosphorus is, like sulphur, a hydrine and not a simple 
body. 
The charcoal of wood is a proto-hydrine. When the sub- 
stance in very fine powder, and mixed with two parts of iron re- 
duced, and one part of oxide of manganese, is made red hot for 
several hours, the latter of these bedies de-hydrogenates it, and 
the former condenses it. The produce of this operation is iron 
alloyed with manganese, and a lamellated friable matter, which 
* Communicated by M. Van Mons, 
is 
