Heat-energizable adhesive compositions comprise a thermoplastic synthetic resin and cellulose nitrate, preferably having a nitrogen content of 10--12,2 per cent, in a suitable solvent mixture. The synthetic resin is preferably a polyhydric alcohol-polybasic acid condensation product, preferably modified with a vegetable drying, semi- or non-drying oil, stearic acid, oleic acid or a higher alcohol, e.g. cocoanut, cottonseed, hydrogenated cottonseed and castor oils, butyl alcohol, hexyl, propyl, amyl and benzyl alcohols, cyclohexanol, and terpineol. Resins modified with rosin or gums, e.g. kauri or copal may also be used. The polyhydric alcohol-polybasic acid resins may be prepared from di- or tri-hydric alcohols or higher alcohols such as sorbitol, or pentaerythritol. Polyhydric ether alcohols, e.g. diethylene glycol, triethylene glycol, monoethylin, monobenzylin, or diethyl ether of sorbitol, pentaerythritol, or diglycerol are particularly suitable. Polybasic acids such as malic, adipic, succinic, trimellitic, dilactylic, fumaric or sebacic acids may be used instead of phthalic acid. Other suitable synthetic resins include aryl sulphonamide formaldehyde resins, e.g. toluene-, xylene- or benzene-sulphonamide formaldehyde resins; vinyl acetate resins; vinyl acetate-vinyl chloride resins; and certain phenol-formaldehyde and urea-formaldehyde resins. The proportion of resin to cellulose nitrate may be varied from 0,6--5 parts to 1 part, preferably 0,6--2,0 parts to 1 part. Plasticizers may be used, if desired, and are preferably of the "solvent" type, e.g. dibutyl phthalate, dibutyl tartrate, tricresyl phosphate, triacetin or ethyl-meta-sulphonamide. According to examples the following compositions are suitable: (1) 8,2 per cent cellulose nitrate (4 secs. viscosity), 10,0 per cent denatured alcohol, 29,0 per cent toluol, 6,4 per cent dibutyl phthalate, 33,0 per cent ethyl acetate, and 13,4 per cent of a synthetic resin obtained by reacting 45,8 per cent phthalic anhydride, 28,8 per cent glycerol and 25,4 per cent castor oil at 225 DEG C. until an acid number of 13--15 was reached. (2) The same ingredients and proportions as in example 1, except that the cellulose nitrate has a viscosity of 2 seconds. (3) Similar ingredients and proportions to example 2, except that the synthetic resin was the reaction product of 40,5 per cent phthalic anhydride, 35,4 per cent stearic acid and 24,1 per cent glycerol. (4) 10,0 per cent cellulose nitrate 3 per cent tricresyl phosphate, 15,0 per cent ethyl acetate, 22,0 per cent toluol, 30,0 per cent alcohol, 20 per cent of the reaction product of 54,3 per cent phthalic anhydride, 24,2 per cent glycerol and 21,5 per cent castor oil heated to 200 DEG C. until an acid number of 73--77 was reached. (5) 10 per cent cellulose nitrate, 20 per cent ethyl acetate, 30 per cent toluol, 28 per cent ethyl alcohol and 12 per cent of the reaction product of 41,7 per cent diethylene glycol and 58,3 per cent phthalic anhydride heated to 240--250 DEG C., to give an acid number of 40. (6) 9,9 per cent cellulose nitrate, 5,8 per cent ethyl alcohol, 40,0 per cent ethyl acetate, 32,6 per cent toluol, 1,2 per cent acetone, 4,4 per cent dibutyl phthalate and 6,1 per cent of the reaction product of 37,4 per cent diethylene glycol, 47,6 per cent phthalic anhydride and 15,0 per cent stearic acid heated to 190--200 DEG C. to give an acid number of 40--50. (7) 10,0 per cent cellulose nitrate, 6,0 per cent alcohol, 37,0 per cent ethyl acetate, 32,5 per cent toluol, 4,5 per cent dibutyl phthalate, 10,0 per cent of synthetic resin as in example 6. (8) 11,3 per cent cellulose nitrate (80 secs. viscosity), 8,6 per cent alcohol, 13,5 per cent dibutyl phthalate, 16,0 per cent toluol, 19,0 per cent ethyl acetate, and 30,7 per cent of synthetic resin as in example 6. (9) 15,0 per cent cellulose nitrate (\ba1/2\be secs. viscosity), 18,0 per cent. alcohol, 31,0 per cent ethyl acetate, 8,0 per cent dibutyl phthalate, 15,0 per cent toluol, and 16,0 per cent toluene-sulphonamideformaldehyde condensation product. The compositions may be coloured or made opaque by the addition of a suitable filler. The adhesives may be applied by brushing, dipping, spraying or roller coating methods and the solvent is then evaporated. The articles may then be united by heat, e.g. temperatures of 130--150 DEG C., and moderate pressure, e.g. 2--15lbs. per sq. inch. Pressures of the order of 50--10,000lbs. per sq. inch may be used to effect union without heat. The above compositions are useful for applying regenerated cellulose sheets to fabric, paper, cardboard, metal foil, regenerated cellulose sheets, leather, tissue paper and cellulose ester films; fabric to fabric, paper, cellulose ester films, fibre board, metal foil and lacquered or rubberized fabric; metal foil to metal foil, wood, paper, cardboard, glass and tissue paper; veneer to wood and fibre board; glass to glass and cellulose ester films. Also they may be used for cementing aluminium foil to various surfaces, e.g. to coat the internal or external surfaces of tanks; to coat pipe-lines or cables, particularly when buried; to coat fabric for use on aircraft; to coat the interior and exterior of refrigerators; as a substitute for goldbeater's skin and to coat wood shingles to improve durability.ALSO:Heat-energizable adhesive compositions comprise a thermoplastic synthetic resin and cellulose nitrate, preferably having a nitrogen content of 10-12,2 per cent in a suitable solvent mixture. The synthetic resin is preferably a polyhydric alcohol-polybasic acid condensation product, preferably modified with a vegetable drying, semi- or non-drying oil, stearic acid, oleic acid or a higher alcohol, e.g. coconut, cottonseed, hydrogenated cottonseed and castor oils, butyl, hexyl, propyl, amyl and benzyl alcohols, cyclohexanol and terpineol. Resins modified with rosin or gums, e.g. kauri or copal may also be used. The polyhydric alcohol-polybasic acid resins may be prepared from di- or tri-hydric alcohols or higher alcohols, e.g. sorbitol or pentaerythritol. Polyhydric ether alcohols, e.g. diethylene glycol, triethylene glycol, monoethylin, monobenzylin, or diethyl ether of sorbitol, pentaerythritol or diglycerol are particularly suitable. Polybasic acids such as malic, adipic, succinic, trimellitic, dilactylic, fumaric or sebacic acids may be used instead of phthalic acid. Other suitable synthetic resins include aryl sulphonamide-formaldehyde resins; vinyl acetate resins; vinyl acetatevinyl chloride resins; and certain phenolformaldehyde and urea formaldehyde resins. The proportion of resin to cellulose nitrate may be varied from 0.6-5 pts. to 1 pt., preferably 0.6-2 pts. to 1 pt. Plasticizers may be used if desired and are preferably of the "solvent" type, e.g. dibutyl phthalate, dibutyl tartrate, tricresyl phosphate, triacetin or ethyl metasulphonamide. According to examples the following compositions are suitable. (1) Cellulose nitrate (4 secs. viscosity), alcohol, toluol, dibutyl phthalate, ethyl acetate and the reaction product of phthalic anhydride, glycerol and castor oil. (2) Similar ingredients to the previous example, except that the cellulose nitrate has a viscosity of 2 secs. (3) Similar to example 2, the resin being the reaction product of phthalic anhydride, stearic acid and glycerol. (4) Cellulose nitrate, tricresyl phosphate, ethyl acetate, toluol, alcohol, and the reaction product of phthalic anhydride, glycerol and castor oil. (5) Cellulose nitrate, ethyl acetate, toluol, ethyl alcohol, and the reaction product of diethylene glycol and phthalic anhydride. (6) Cellulose nitrate, ethyl alcohol, ethyl acetate, toluol, acetone, dibutyl phthalate and the reaction product of diethylene glycol, phthalic anhydride and stearic acid. (7) Cellulose nitrate, alcohol, ethyl acetate, toluol, dibutyl phthalate, synthetic resin as in example 6. (8) Cellulose nitrate (80 secs. viscosity), alcohol, dibutyl phthalate, toluol, ethyl acetate and synthetic resin as in example 6. (9) Cellulose nitrate ( 1/2 sec. viscosity), alcohol, ethyl acetate, dibutyl phthalate, toluol and toluene sulphonamide-formaldehyde condensation product. The compositions may be coloured or made opaque by the addition of a suitable filler, and may be applied by brushing, dipping, spraying or roller coating methods and the solvent is then evaporated. The articles may then be united by heat, e.g. temperatures of 130-150 DEG C., and moderate pressure, e.g. 2-15 lbs. per sq. inch. Pressures of the order of 50-10,000 lbs. per sq. inch may be used to effect union without heat. Specified applications of the compositions for adhesive purposes are given in the Specification.