50 On the new discovered Substance called Iode. 
vapour of iode, and it produces hydrogen gas -equal in volume te 
the half of the acid gas. A few minutes agitation are sufficient to 
decompose it entirely. Iron and zine produce a similar effect. 
This acid in the liquid state, obtained by dissolving the gas in 
water, forms, as is said above, a very dense liquid not very vola- 
tile: it rapidly decomposes the carbonates, and dissolves iron 
and zine with an extrication of hydrogen gas: but it dees not 
attack mercury even when warm; which proves that it has a 
strong affinity for water. It forms with barytes a soluble salt, 
and it gives with corrosive sublimate a red precipitate soluble in 
an excess of acid. When we pour into it some drops of oxy- 
muriatic acid, the new substance is instantly regenerated: when 
heated with black oxide of manganese, the red and brown oxides 
of lead, iode is disengaged, and the oxides are reduced into the 
state in which they are generally soluble in the acids. The red 
oxide of mercury makes the acid pass to iode, and we may con- 
clude that all the oxides which cause the muriatic acid to pass 
to that of oxymuriatic will also pass a portion of the new acid 
to the state of iode.. Finally, this acid dissolved in water, and 
subjected to the action of the Voltaic pile, appears at the positive 
pole in the state of iode. When once engaged ina combination, 
it is not easy to separate it. The sulphuric acid, for example, 
when placed in contact with the combination of the new acid, 
and with potash, gives sulphurous acid, and the new substance is 
liberated: the nitric gives nitrous acid. If we employ the phos- 
phorie and boric acids, dry or dissolved in water, they produce 
no decomposition. 
It is now easy to conceive what happens when iode is placed 
in contact with other bodies. 
With hydrogen at a high or low temperature we obtain the 
new acid; but it is net usually pure, because it has the property 
of dissolving a great quantity of iode, which resists the action of 
hydrogen. 
Sulphuretted hydrogen speedily takes the colour from iode, 
and makes it pass to the state of acid, depositing abundance of 
sulphur: it also produces the same effect when the new sub- 
stance is in combination with the alkalis, forming brown or 
colourless solutions. It is to be remarked, that when we preci- 
pitate by the sulphuretted hydrogen gas a solution of iode in 
ether or alcohol, sulphur is not deposited in any sensible quantity. 
The sulphurous acid speedily converts iode into acid, passing 
itself to the state of sulphurie acid *. The phosphorous acid and 
the sulpluretted sulphites also give existence to a new acid, 
* This assertion contradicts a fact stated in the next paragraph. Pos- 
sibly the sulphurous and sulphuric acid should be transposed, Epir. 
Hence 
