Abstract: The invention relates to novel monoesters and diesters of 9,10-endoethano-9,10-dihydroanthracene-11,11-dicarboxylic acid.These novel monoesters and diesters correspond to the following structural chemical formula (II): ##STR1## in which R.sup.1 and R.sup.2 are identical or different and can represent H, an alkali metal or alkaline earth metal atom, a linear or branched alkyl group having from 1 to 6 carbon atoms, an alicyclic group having form 3 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, defined in their cis or trans variety, or an alkynyl group having from 2 to 6 carbon atoms, the said groups optionally being substituted by one or more functional groups such as ether, epoxide, halogeno, cyano, ester, aldehyde, ketone, aryl etc., where R.sup.1 and R.sup.2 cannot be H or ethyl simultaneously. These addition products constitute valuable intermediates for the preparation of methylidenemalonates in high yields and with a high purity.

Abstract: The invention relates to novel monoesters and diesters of 9,10-endoethano-9,10-dihydroanthracene-11,11-dicarboxylic acid.These novel monoesters and diesters correspond to the following structural chemical formula (II): ##STR1## in which R.sup.1 and R.sup.2 are identical or different and can represent H, an alkali metal or alkaline earth metal atom, a linear or branched alkyl group having from 1 to 6 carbon atoms, an alicyclic group having from 3 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, defined in their cis or trans variety, or an alkynyl group having from 2 to 6 carbon atoms, the said groups optionally being substituted by one or more functional groups such as ether, epoxide, halogeno, cyano, ester, aldehyde, ketone, aryl etc., where R.sup.1 and R.sup.2 cannot be H or ethyl simultaneously. These addition products constitute valuable intermediates for the preparation of methylidenemalonates in high yields and with a high purity.

Abstract: 5-(2-methyl-2-thiol ethyl) hydantoin and derivatives thereof are useful in the treatment of evolutive chronic polyarthritis.

Abstract: An insulating stay comprises: a central core (1) having high electrical resistance and high tensile strength; a sheath (2) of high electrical resistivity and comprising fins (3) to offer a maximum resistance path to possible surface current losses; and end fittings (4). The central core is made of resin reinforced with long, continuous fibers, and advantageously of epoxy resin reinforced with glass fibers. The sheath (2) is made of a natural or synthetic polymer, and advantageously of EPDM elastomer. The stay is manufactured by coating the central core (1) with a high viscosity glue (8) having high longitudinal resistivity, then wrapping said glue-covered core in a hollow tube (5) of raw elastomer and placing the assembly in a mold (5) where said fins (3) are formed in the sheath (2) and where the raw elastomer (5) is polymerized by vulcanization or reticulation. The stay is intended for bracing electrical installations that need to be insolated and placed at some distance from the ground.

Abstract: The central cavity of the furnace is provided from the periphery to the center with a first thermal insulation, at least one element of doped lanthanum chromite, a second thermal insulation and at least one element of stabilized zirconia or thoria which permits operation of the furnace at about 2000.degree. C.

Abstract: Safety device for a compressed gas tank comprising a membrane influenced by an elastic effort and resting simultaneously on two concentric seats. It is characterized in that the applying of the pressure to the seat having the smallest diameter corresponds to a sealing position and that the applying of the pressure to the seat having the greatest diameter causes a sudden opening of the device.