Abstract: A nematic liquid crystal composition having a resistivity of about 1 .times. 10.sup.8 to 1 .times. 10.sup.10 ohm-cm and a broad mesophase comprising a mixture prepared by transiminization between at least one Schiff base compound of the formula ##SPC1##And at least one other Schiff base of the formula: ##SPC2##Wherein R, R.sup.1, R.sup.2 and R.sup.3 are alkyl radicals having 1 to 18 carbon atoms. Advantageously the Schiff bases I and II are subjected to transiminization at a molar ratio of about 5/1 to 1/5.

Abstract: Ammonium mercaptoalkanesulfonate salts having the formula: HS--R--SO.sub.3 .sup.-NH.sub.4 .sup.+ are new salts prepared by a novel process comprising reaction of a thioamide, such as a thioalkanamide or thioarylamide, with a sultone in alcohol. Typical examples comprise reacting thioacetamide with 1,3-propane sultone (for ammonium 3-mercaptopropanesulfonate); with 2,4-butane sultone (for ammonium 3-mercapto-1-methylpropanesulfonate); and with 1,4-butane sultone (for ammonium 4-mercapto-2-butanesulfonate.) The product can be recovered by precipitation with a nonsolvent for the product such as ether, benzene, or ligroine, followed by filtration. The new ammonium salts in aqueous solution are useful as silver complexing agents for photographic fixing or stabilizing, and are more active than the known alkali metal and guanidinium salts, thus providing a new method of fixing developed silver halide photographic elements.

Abstract: An electrolytic cell for recovering silver from photographic processing solutions comprising an assembly of two or more spaced electrodes which are mounted on support rods and carried within a perforate or imperforate housing. Each electrode comprises a support member such as a frame, one or more sheets of porous flexible material carried by said support member, and a plurality of filaments of electrically conductive material such as carbon distributed across the area of the sheet or sheets, and captured between a sheet and the support member, or between two sheets. The entire electrolytic cell can be formed of combustible materials, and the deposited silver can be recovered after burning the cell.