proportions found general acceptance as an empirical fact; but
many of the leading lights of chemistry still looked askance at
Dalton's explanation of this law. Thus Wollaston, though from the
first he inclined to acceptance of the Daltonian view, cautiously
suggested that it would be well to use the non-committal word
"equivalent" instead of "atom"; and Davy, for a similar reason,
in his book of 1812, speaks only of "proportions," binding
himself to no theory as to what might be the nature of these
proportions.

At least two great chemists of the time, however, adopted the
atomic view with less reservation. One of these was Thomas
Thomson, professor at Edinburgh, who, in 1807, had given an
outline of Dalton's theory in a widely circulated book, which
first brought the theory to the general attention of the chemical
world. The other and even more noted advocate of the atomic
theory was Johan Jakob Berzelius. This great Swedish chemist at
once set to work to put the atomic theory to such tests as might
be applied in the laboratory. He was an analyst of the utmost
skill, and for years be devoted himself to the determination of
the combining weights, "equivalents" or "proportions," of the
different elements. These determinations, in so far as they were
accurately made, were simple expressions of empirical facts,
independent of any theory; but gradually it became more and more
plain that these facts all harmonize with the atomic theory of
Dalton. So by common consent the proportionate combining weights
of the elements came to be known as atomic weights--the name
Dalton had given them from the first--and the tangible conception
of the chemical atom as a body of definite constitution and
weight gained steadily in favor.