Avogadro (Equal volumes of all gases at the same temperature and pressure contain equal number of molecules)
Robert Boyle (Relation between pressure and volume in gases)
Jaques Charles (An experimental gas law which describes how gasses tend to expand when heated.)
Thomas Graham (The rate of effusion of a gas is inversely proportional to the square root of the mass of its particles.)
John Dalton (In a mixture of ideal gases, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. The total pressure of a gas mixture is the sum of the partial pressures of each individual gas in the mixture.)
William Henry (At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.)
Connect is that all proposed laws related to gases (or effect on gases when heated). Whew.