500,549. Weed - killers; stabilizing aromatic nitro hydroxy - compounds. TRUFFAUT, G., and PASTAC, I. Aug. 5, 1937, No. 21615. [Class 81 (i)] [Also in Group IV] Certain aromatic nitro-hydroxy-compoundrs for use as weed killers are stabilized by the addition of a relatively small quantity of an alkali metal salt of an oxy-acid of a metal of the fifth or sixth periodical group. The nitro compounds specified are 1 hydroxy-2-nitrobenzene and its isomers; 4.6-di-nitro-1,3- dihydroxy benzene; the various mono-nitro methyl-hydroxy benzenes; 1-hydroxy 4-nitro naphthalene; di-nitro-1-hydroxy-naphthalene mono- and poly-nitro-2-hydroxy-naphthalene 1-hydroxy-2-chloro-4-vitro-benzene ; 1-hydroxy-2-4-di-nitro-6-chloro benzene ; and 1-hydroxy-2-nitroso-4-nitro-naphthalene. The stabilizers may be chromates, bichromates, molybdates, arsenates, or vanadates. Fertilizers, insecticides, fungicides, and surface tension reducers such as sulphoricinates, sulphonated higher alcohols or alkylated naphthalene sulphonic acids may be added. The products may be used in solution, or in powder form with a diluent such as steatite. According to an example 1 - hydroxy - 2 - 4 - di - nitro -naphthalene, potassium bichromate and potassium carbonate are dissolved in water. Reference is made to the prior use of mixtures of alkali or calcium chlorates mixed with alkali or calcium chlorides or carbonates, of mixtures of sulphuric acid with potassium sulphate, and of arsenates mixed with iron or aluminium hydroxide. British Specifications 141,728, 334,202, [both in Class 140], and 425,295, and U.S.A. Specification 1,935,495 are referred to.