Assertion: atom's mass | /r/HasAspect | same proportions
Facets:
value: by weight
type: OTHER
value: always
type: TEMPORAL
Source sentences:
text: First established by the French chemist Joseph Louis Proust in 1799, this law states that if a compound is broken down into its constituent chemical elements, then the masses of the constituents will always have the same proportions by weight, regardless of the quantity or source of the original substance.