The mental surroundings of the chemists of that age did not allow them fully to appreciate the work of Avogadro.
In 1843 Charles Gerhardt proposed to use the law of Avogadro as a basis for the determination of atomic weights.
Like the atomic theory itself, Avogadro's law is an outcome of physical work and of physical reasoning.
In 1811 Avogadro distinguished between the ultimate particles of compounds and elements.
According to Avogadro the water vapor contains twice as many atoms of hydrogen as of oxygen.
We make use of Avogadro's law and of the definition of "atom" which has been deduced from it (see p. 142).
This number, by the way, is known to science as "Avogadro's Constant."
This deduction from Avogadro's law is now a part and parcel of our general chemical knowledge.
Avogadro's hypothesis gave the chemist a definition of "molecule;" it also gave him a definition of "atom."
It is to the molecule, considered as the unit of physical structure, that Avogadro's law applies.