12 
ORIGINAL COMMUNICATIONS. 
carbon; while in that of phosphorus or arsenic, both volatiliza- 
ble, it forms acids which are comparatively insusceptible of 
volatilization? Wherefore does not hydrogen produce an acid 
with phosphorus and arsenic, as well as with sulphur? 
According to Berzelius, all the halogen bodies produce 
with hydrogen combinations which are as highly endowed 
with the attributes of acidity, as the strongest acids into which 
oxygen enters as a constituent. It is conceded in his 
letter that his language respecting these combinations can- 
not be reconciled with his declaration in one place that they 
do not combine with oxybases, and in another that a body 
which cannot so combine is not an acid. It strikes me, that 
the only way in which the admitted inconsistency of his de- 
scription of these bodies, with his definition of acidity, can be 
avoided, is by assuming that they combine as acids with haloid 
bases, although decomposed by oxybases. 
I will now proceed to comment on a new subject for con- 
sideration, presented in Berzelius's letter in reply to mine. 
It must be evident that every oxysalt, composed of an 
oxacid and an oxybase, must consist of an atom of each radical, 
and as many atoms of oxygen as exist both in the acid and in 
the base. Thus sulphate of potash consists of an atom of po- 
tassium, an atom of sulphur and four atoms of oxygen, and may 
be represented either by SOOO KO or SOOOOK. 
Berzelius in his letter repeats an ingenious suggestion pre- 
viously advanced in his treatise, that SOOOO, (sulphur with 
four atoms of oxygen,) may act, as a compound halogen body 
like cyanogen, and thus form a salt by union with an atom 
of any radical. He conceives that the apparent want of ana- 
logy, which induced him to separate into two classes, the am- 
phigen and halogen bodies, disappears under this view of the 
phenomena ; and that his amphide salts might be consi- 
dered as constituted of a compound halogen body and an ele- 
mentary radical. But however we may admire the ingenuity 
of these suggestions, ere, in obedience to them, we extend the 
limits of the halogen class, I would request that the word 
salt should be defined, and that it be shown that consistently 
