Cyclic compounds containing four methylene or substituted methylene groups, a keto group and an ether oxygen atom are used as solvents, or softening, swelling or plasticizing agents in the manufacture or treatment of articles and products having a basis of nitrocellulose, cellulose acetate and other cellulose esters and ethers. The compounds are termed oxanones, the simplest being 1 : 4-oxanone or tetrahydropyrone. The substituting groups may be alkyl, aralkyl or aryl, or carboxylic ester groups. Examples of substituted oxanones are: 2 : 6-dimethyl - 1 : 4 - oxanone; 1 : 4-oxanone-2 : 6-dicarboxylic acid diethyl ester; 2-dimethyl-1 : 4-oxanone-6-carboxylic acid ethyl ester; 2 : 6-dimethyl - 1 : 4 - oxanone - 3 : 5 - dicarboxylic acid diethyl ester; 2 : 6-dimethyl-1 : 4-oxanone 3 : 5-dicarboxylic acid dibutyl ester; 2 : 6-dimethyl-1 : 4-oxanone - 3 : 5 - dicarboxylic acid di-iso-amyl ester; 3 : 5-dibenzal-1 : 4-oxanone; 2 : 6-diphenyl - 3 : 5 - dimethyl - 1 : 4 - oxanone; 2 : 6 - diphenyl - 3 : 5 - dimethyl - 3 : 5-dibrom1 : 4-oxanone; and also compounds in which the substituent groups themselves form a further ring. The oxanones may be used in the preparation of dopes, varnishes, lacquers, &c., and of solutions for the manufacture of artificial threads, filaments, ribbons, films, foils, sheets, &c., by dry or wet spinning processes, and for such manufactures they may be used in conjunction with other plasticizers and with other solvents of high, medium, low or very low boiling point, and also with diluents; and in the solutions there may be included dyestuffs, white or coloured pigments, natural or synthetic resins, and substances to reduce the inflammability of the product although the halogenated and especially the brominated oxanones serve to plasticize the cellulose derivative and to reduce its inflammability. For the manufacture of artificial filaments, ribbons, &c., by dry spinning processes, the oxanones are generally employed in small proportions and in conjunction with volatile solvents; but when wet spinning, they may be used as the sole solvent, and the process of spinning may be conducted in the manner described in Specifications 179,234, [Class 2 (ii), Cellulose &c.], 340,324 and 340,325, and the oxanones may be employed not only in the spinning solutions but also in a subsequent treatment bath as described in Specification 340,437. The oxanones may be used as the plasticizing agent in the preparation of plastics and moulding powders, and for this purpose the less volatile substituted oxanones such as alkylated oxanone dicarboxylic acid esters, are especially suitable. The oxanones are also of use in the treatment of formed articles or materials such as filaments, yarns, ribbons, films and fabrics. Such treatments are, for example, to prevent laddering or splitting of knitted fabrics as described in Specification 280,990, [Class 2 (ii), Cellulose &c.], for improving the pliability and extension of filaments &c. particularly the knitting properties of artificial horsehair and other thick filaments, and in particular while allowing shrinkage of the material to take place as described in Specification 389,823; for increasing the tenacity of filaments and other products in association with the stretching of the materials either as a single operation, or gradually, or by stages as described in Specification 370,430, or as warps as described in Specification 371,461; in the lubrication of yarns &c. by the addition of oxanones to the sizes, which may contain as thickening agents polymerized vinyl compounds or oxidized linseed oil or other drying oils; for increasing the absorptive power of the materials for liquid and solid substances in the processes of dyeing, printing, mordanting, discharging, loading and delustering, in particular for increasing the absorptive capacity for acid wool, direct cotton and vat dyestuffs, for pigments such as titanium oxide, and for discharges such as formaldehyde sulphoxylate discharges; and for use in relustering delustered materials as described in Specification 259,265, [Class 2 (ii), Cellulose &c.]. In examples for the preparation of a cellulose acetate plastic, a solution in benzene-alcohol of 2 : 6-dimethyl-1 : 4-oxanone-3 : 5-dicarboxylic acid dibutyl or di-iso-amyl ester is sprayed on to or otherwise incorporated with acetone-soluble cellulose acetate, the mass being worked up as usual and moulded into sheets, rods, blocks, etc.; lacquers or insulating compositions for electrical conductors consist of cellulose acetate, polymerized vinyl acetate, 2 : 6-dimethyl-1 : 4-oxanone-3 : 5-dicarboxylic acid dibutyl or di-iso-amyl ester, acetone, alcohol and benzene, or of cellulose acetate, diphenylol propane formaldehyde synthetic resin, tricresyl phosphate, diphenylol propane, 1 : 4-oxanone and acetone, or of nitrocellulose, diphenylol propane formaldehyde synthetic resin, 2 : 6-dimethyl-1 : 4-oxanone-3 : 5-dicarboxylic acid dibutyl or di-iso-amyl ester, triphenyl phosphate, acetone and butyl acetate; a lacquer composition for producing a highly flexible film or coating particularly suitable for covering rubber insulated cables consists of cellulose acetate, diphenylol propane formaldehyde resin, dibutyl tartrate, tricresyl phosphate, 1 : 4-oxanone, dioxane and acetone; a composition for dry spinning artificial filaments with stretching consists of cellulose acetate, 1 : 4-oxanone and acetone; artificial filaments are made by extruding an acetone solution of cellulose acetate which may contain 1 : 4-oxanone, into an aqueous or alcoholic solution of 1 : 4-oxanone, and after stretching washing out the oxanone by means of a more dilute solution of the same solvent; filaments or yarns of cellulose acetate in hank or other form are soaked in aqueous or alcoholic 1 : 4-oxanone solution and then stretched; a cellulose acetate fabric is printed with a paste consisting of dyestuff or pigment, 1 : 4-oxanone, diethylene glycol, water and gum arabic, is then dried at 85-95 DEG C. to evaporate the oxanone, and is finally washed, soaped and dried, producing a printed fabric the lustre of the printed parts being restored if the fabric contains delustred yarns; in the last example, the dyestuff may be a typical cellulose acetate dyestuff, such as a member of the aminoanthraquinone series, or a nitro diarylamine, or an acid wool or direct cotton dyestuff, and the pigment may be titanium oxide. The first Provisional Specification refers to the production and use of the simpler cyclic compound containing but two methylene groups, and it also refers to the production of this compound and to the oxanones in general by the dehydration of the corresponding dioxy aliphatic ketones conveniently by heating or boiling with a strong condensing agent such as zinc chloride or phosphoric acid, or by passing the vapour or the dioxy ketone over a dehydrating catalyst such as alumina, or zinc chloride heated to 200-400 DEG C., the dioxy ketones being obtained by thermal decomposition of salts of the corresponding oxyaliphatic acids, for example, glycollic and hydracrylic acids.ALSO:Cellulose ester and ether lacquers, dopes, varnishes, &c. are prepared with the use as solvent or plasticizing agent of cyclic compounds containing four methylene or substituted methylene groups, a keto group and an ether oxygen atom. The compounds are termed oxanones, the simplest being 1.4-oxanone or tetrahydropyrone. The substituting groups may be alkyl, aralkyl, or aryl, or carboxylic ester groups. The oxanones may be used in conjunction with other plasticizers and with other solvents of high, medium or low boiling-point, and also with diluents; and in the solutions there may be included dyestuffs, white or coloured pigments, natural or synthetic resins, and substances to reduce the inflammability of the product although the halogenated and especially the brominated oxanones serve both to plasticize the cellulose derivative and to reduce its inflammability. In examples, lacquers and insulating compositions for electric conductors consist of cellulose acetate, polymerized vinyl acetate, 2,6-dimethyl-1,4-oxanone-3,5-dicarboxylic acid dibutyl or di-isoamyl ester, acetone, alcohol, and benzene; or of cellulose acetate, diphenylol propane formaldehyde synthetic p resin, tricresyl phosphate, diphenylol propane, 1:4-oxanone and acetone; or of nitrocellulose, diphenylol propane formaldehyde synthetic resin, 2,6-dimethyl-1,4-oxanone-3,5-dicarboxylic acid dibutyl or di-isoamyl ester, triphenyl phosphate, acetone, and butyl acetate; or of cellulose acetate, diphenylol propane formaldehyde synthetic resin, dibutyl tartrate, tricresyl phosphate, 1,4-oxanone, dioxane, and acetone. The first Provisional Specification refers to the use of the simpler dioxanone containing but two methylene groups.ALSO:Cellulose ester and ether plastics are prepared with the use as solvent or plasticizing agent of cyclic compounds containing four methylene or substituted methylene groups, a ketone group, and an ether oxygen atom. The compounds are termed oxanones, the simplest being 1,4-oxanone or tetrahydropyrone. The substituting groups may be alkyl, aralkyl or aryl, or carboxylic ester groups. The oxanones may in the preparation of plastics and moulding powders be used in conjunction with other solvents and plasticizers; and for such uses the less volatile substituted oxanones such as the alkylated oxanone dicarboxylic acid esters are especially suitable; and they may be used with the addition of substances which reduce the inflammability of the product although the halogenated and especially the brominated oxanones serve both to plasticize the cellulose derivative and to reduce its inflammability. The oxanones may also be used as additions to sizes used with cellulose acetate and other cellulose ester and ether textiles &c., for the purpose of lubricating the materials,