Lacquers, varnishes and coating compositions are prepared by incorporating a cellulose derivative with a synthetic resin obtained by condensing an hydroxyaromatic alcohol with the reaction product of an aldehyde and glycerol or polyglycerol. Plasticizers, softeners, solvents, fire retardents, colouring matters and other resins both natural and synthetic may also be present. The hydroxyaromatic alcohols, of which hydroxybenzyl alcohol, hydroxytolyl alcohol and hydroxyxylyl alcohol are specified, are preferably condensed at elevated temperatures and in the presence of an acid or alkali, e.g. ammonium hydroxide, with an equimolecular quantity of the aldehyde-glycerol, e.g. that obtained by heating glycerol or polyglycerol with trioxymethylene. The cellulose derivative may comprise the nitrate, acetate, formate, propionate, butyrate or other ester, or methyl-cellulose, ethyl-cellulose, benzyl-cellulose or other ether. Of the solvents which may be used are mentioned acetone, alcohol, benzene, ethylene dichloride, ethyl acetate, ethyl lactate, tetrachlorethane and diacetone alcohol. Instances of plasticizers are diphenylolpropane, triacetin, dibutyl tartrate, diethyl phthalate and xylene monomethylsulphonamide. Resins mentioned are the artificial resins from phenol-formaldehyde and diphenylolpropaneformaldehyde, and the natural resins manila, acaroid, pontianak, kauri, dammar, rosin, shellac and ester gums. Brominated organic compounds, e.g. brominated tricresyl phosphate, are referred to as fire retardants. Examples are given of the preparation of (1) coating compositions comprising (a) cellulose acetate, synthetic resin and acetone, (b) cellulose acetate, synthetic resin, acetone, benzene, alcohol and diacetone alcohol, (c) cellulose nitrate, camphor, diethyl phthalate, synthetic resin, benzene, alcohol, butyl alcohol, butyl acetate and ethyl acetate; (2) a coloured lacquer consisting of cellulose acetate, synthetic resin, diphenylolpropane, pigment, acetone, ethyl acetate, benzene, toluene and ethyl lactate. In each of the examples the proportions of the constituents are given, whilst the synthetic resin used is that whose preparation is described above.ALSO:Lacquers, varnishes, coating compositions, adhesives, plastic materials, filaments and photographic or other films are prepared by incorporating a cellulose derivative with a synthetic resin obtained by condensing an hydroxyaromatic alcohol with the reaction product of an aldehyde and glycerol or polyglycerol. Plasticizers, softeners, solvents, fire retardants, colouring matters and other resins both natural and synthetic may also be present. The hydroxyaromatic alcohols, of which hydroxybenzyl alcohol, hydroxytolyl alcohol and hydroxyxylyl alcohol are specified, are preferably condensed at elevated temperature and in the presence of an acid or alkali, e.g. ammonium hydroxide, with an equimolecular quantity of the aldehyde-glycerol, e.g. that obtained by heating glycerol or polyglycerol with trioxymethylene. The cellulose derivative may comprise the nitrate, acetate, formate, propionate, butyrate or other ester, or methyl-cellulose, ethyl-cellulose, benzyl-cellulose or other ether. Of the solvents which may be used are mentioned acetone, alcohol, benzene, ethylene dichloride, ethyl acetate, ethyl lactate, tetrachlorethane and diacetone alcohol. Instances of plasticizers are diphenylolpropane, triacetin, dibutyl tartrate, diethyl phthalate and xylene monomethylsulphonamide. Resins mentioned are the artificial resins from phenol-formaldehyde and diphenylolpropane-formaldehyde, and the natural resins manila, acaroid, pontianak, kauri, dammar, rosin, shellac, and ester gums. Brominated organic compounds, e.g. brominated tricresyl phosphate, are referred to as fire-retardants. The filaments may be prepared from solutions containing the synthetic resin and a cellulose derivative by dry or wet spinning methods. Compositions containing the synthetic resin and a cellulose derivative are particularly suitable in the manufacture of reinforced glass, either for the production of the reinforcing sheets or for cementing the sheets to the glass. Examples are given of the preparation of (1) coating compositions comprising (a) cellulose acetate, synthetic resin and acetone, (b) cellulose acetate, synthetic resin, acetone, benzene, alcohol and diacetone alcohol, (c) cellulose nitrate, camphor, diethyl phthalate, synthetic resin, benzene, alcohol, butyl alcohol, butyl acetate and ethyl acetate; (2) adhesives useful for securing sheets of a cellulose derivative to glass, cardboard, asbestos and metal e.g. in the preparation of reinforced glass, consisting of (a) cellulose acetate, synthetic resin, acetone, ethyl acetate and ethyl lactate, (b) cellulose nitrate, camphor, dibutyl phthalate, synthetic resin, benzene, alcohol, butyl alcohol, butyl acetate and ethyl acetate; (3) a plastic composition comprising cellulose acetate, synthetic resin, xylene monomethylsulphonamide, alcohol and benzene; (4) a solution, suitable for the production of filaments by dry spinning, consisting of cellulose acetate, synthetic resin and acetone; (5) a coloured lacquer consisting of cellulose acetate, synthetic resin, diphenylolpropane, pigment, acetone, ethyl acetate, benzene, toluene and ethyl lactate. In each of the examples the proportions of the constituents are given, whilst the synthetic resin used is that whose preparation is described above.ALSO:Adhesives and plastic materials are prepared by incorporating a cellulose derivative with a synthetic resin obtained by condensing an hydroxyaromatic alcohol with the reaction product of an aldehyde and glycerol or polyglycerol. Plasticizers, softeners, solvents, fire retardants, colouring matters and other resins both natural and synthetic may also be present. The hydroxyaromatic alcohols, of which hydroxybenzyl alcohol, hydroxytolyl alcohol and hydroxyxylyl alcohol are specified, are preferably condensed at elevated temperature and in the presence of an acid or alkali, e.g. ammonium hydroxide, with an equimolecular quantity of the aldehyde-glycerol, e.g. that obtained by heating glycerol or polyglycerol with trioxymethylene. The cellulose derivative may comprise the nitrate, acetate, formate, propionate, butyrate or other ester, or methylcellulose, ethyl-cellulose, benzyl-cellulose or other ether. Of the solvents which may be used are mentioned acetone, alcohol, benzene, ethylene dichloride, ethyl acetate, ethyl lactate, tetrachlorethane and diacetone alcohol. Instances of plasticizers are diphenylolpropane, triacetin, dibutyl tartrate, diethyl phthalate and xylene monomethylsulphonamide. Resins mentioned are the artificial resins from phenolformaldehyde and diphenylolpropane-formaldehyde, and the natural resins manila, acaroid, pontianak, kauri, dammar, rosin, shellac and ester gums. Brominated organic compounds, e.g. brominated tricresyl phosphate, are referred to as fire retardants. Compositions containing the synthetic resin and a cellulose derivative are particularly suitable in the manufacture of reinforced glass, either for the production of the reinforcing sheets or for cementing the sheets to the glass. Examples are given of the preparation of (1) adhesives useful for securing sheets of a cellulose derivative to glass, cardboard, asbestos and metal, e.g. in the preparation of reinforced glass, consisting of (a) cellulose acetate, synthetic resin, acetone, ethyl acetate and ethyl lactate, (b) cellulose nitrate, camphor, dibutyl phthalate, synthetic resin, benzene, alcohol, butyl alcohol, butyl acetate and ethyl acetate; (2) a plastic composition comprising cellulose acetate, synthetic resin, xylene monomethylsulphonamide alcohol and benzene. In each of the examples the proportions of the constituents are given, whilst the synthetic resin used is that whose preparation is described above.