Assuming that the shapes of weak methane lines are determined by hydrogen and helium and helium collisional broadening, the value of H/He in the Jovian atmosphere is found to be much greater than unity. A preliminary interpretation of differences in the amount of absorption by a strong methane band over the disk of the planet leads to an estimation of height differences of 18 km over the Great Red Spot and 12 km over the equatorial zone. The yellow coloration observed on Jupiter and Saturn in compared with the properties of ammonium sulfide (NH4)2S, a compound that may occur in the atmospheres of these planets.