li. Four
additional repetitions of the process, however, convinced me that there
was likewise some other cause for the presence of this last substance;
for it continued to appear to the last in quantities sufficiently
distinguishable, and apparently equal in every case. I had used every
precaution, I had included the tube in glass vessels out of the reach of
the circulating air; all the acting materials had been repeatedly washed
with distilled water; and no part of them in contact with the fluid had
been touched by the fingers.

"The only substance that I could now conceive as furnishing the fixed
alkali was the water itself. This water appeared pure by the tests of
nitrate of silver and muriate of barytes; but potash of soda, as is
well known, rises in small quantities in rapid distillation; and the
New River water which I made use of contains animal and vegetable
impurities, which it was easy to conceive might furnish neutral
salts capable of being carried over in vivid ebullition."(1) Further
experiment proved the correctness of this inference, and the last doubt
as to the origin of the puzzling chemical was dispelled.

Though the presence of the alkalies and acids in the water was
explained, however, their respective migrations to the negative and
positive poles of the battery remained to be accounted for. Davy's
classical explanation assumed that different elements differ among
themselves as to their electrical properties, some being positively,
others negatively, electrified. Electricity and "chemical affinity," he
said, apparently are manifestations of the same force, acting in the one
case on masses, in the other on particles. Electro-positive particles
unite with electro-negative particles to form chemical compounds, in
virtue of the familiar principle that opposite electricities attract
one another. When compounds are decomposed by the battery, this mutual
attraction is overcome by the stronger attraction of the poles of the
battery itself.

This theory of binary composition of all chemical compounds, through the
union of electro-positive and electro-negative atoms or molecules,
was extended by Berzelius, and made the basis of his famous system of
theoretical chemistry. This theory held that all inorganic compounds,
however complex their composition, are essentially composed of such
binary combinations. For many years this view enjoyed almost undisputed
sway. It received what seemed strong confirmation whe