In chemistry, the law of definite proportions, sometimes called Proust's Law, states that a chemical compound always contains exactly the same proportion of elements by mass. An equivalent statement is the law of constant composition, which states that all samples of a given chemical compound have the same elemental composition. For example, oxygen makes up 8/9 of the mass of any sample of pure water, while hydrogen makes up the remaining 1/9 of the mass. Along with the law of multiple proportions, thelaw of definite proportions forms the basis of stoichiometry. (wikipedia)
See Also
3.13 - Reciprocals and Proportions of Motions and Substance
6.8 - Proportionate and Relative Geometries
9.12 - Velocity of Sound and its Propagation Rate are Proportional
12.00 - Reciprocating Proportionality
13.15 - Principle of Proportion
Figure 14.10 - Proportionate Tonal Relations dictate Contraction or Expansion
Figure 6.17 - Areas and Volumes - Relations and Proportions
Figure 6.19 - Sphere to Cube - Relations and Proportions
Law of Definite Proportions
law of multiple proportions
Laws
Proportion
Reciprocating Proportionality
Table 2 - Controlling Modes and Proportions