Gallium sulphate has been combined with hydroxylamine sulphate and sulphates of primary, secondary and tertiary aliphatic amines. Hydroxylamine has yielded an slum crystallising from water with 24 molecules of water. The double sulphates con­taining amine sulphates contain less than 24 molecules of water, some containing 16 and others 18 molecules. Double sulphates of two primary, one secondary and two tertiary amities have been obtained.