Mr. Davy’s Hypothesis of Electro-chemical Affinity. 255 
both ends, was placed horizontally on a small glass pillar; 
the ends of the platina wire projected beyond the extremi- 
ties of the tube, and terminated in two emall hooks. From 
these hooks on each side were suspended small bell-glasses, 
in each of which was contained a platina wire sealed at the 
top; the latter wire passed through the bell..and formed the 
connexion with the hooks. The lower ends of the bells, 
which were open, were immerged in small glasses, and both 
bells and glasses were filled with distilled water. The con- 
ducting wires which proceeded from the battery were armed 
with a “slender piece of well-burnt charcoal. Each piece 
of charcoal was plunged in the water of the glasses ;—so 
that the electricity was conveyed from the charcoal to the 
wire in the bell. Here the decomposition commenced. The 
electricity was conducted through the wire in the hori- 
zontal tube; from thence to the wire in the second bell, 
where another decomposition took place, and at length to 
the other piece of charcoal. {See the Plate.] 
By this arrangement the middle point, where Mr. Davy 
says water is recomposed, was muriate of lime, which 
would absorb any water that might he formed, and here it 
might reasonably be expected to be found. 
“Having ascertained the exact weight of the horizontal 
tube and its contents, I connected to the apparatus a bat- 
tery of 100 pairs of 4-inch plates. The battery was kept 
in a state of activity for four hours., At the end of this 
time oxygen was found in one bell, and hydrogen in the 
other. But the horizontal tube was precisely the same 
weight as before, notwithstanding that a considerable 
quantity of water had been decomposed. 
The positive wire attracted the negative oxygen, and re- 
pelled the positive bydrogen, through the wire and muriate 
of lime; where meeting with nevative oxygen repelled 
from the other bell, the “two gases, being in different clec- 
trical states, must awe, as Mr. Davy allows, united to form 
water. As the horizontal tube oained no weight at the 
end of the experiment, is it not a sufficiently w el! warranted 
conclusion that no water was formed, and that conse- 
quently the theory given for the evolution. of pure oases 
must be erroneous? These gases, if conveyed throweh the 
wires, must have passed through no less than four air-t tight 
sealings. Why should these gases pass, and air be detained? 
We now come to the second position, That decomposi- 
tion is produced by bringing one of the combined sub- 
stances into a state different from that which is natural to it. 
When a particle of a compound has its elements thus 
brought 
