TECHNOLOGY FOCUS - POLYMERS - Preferred Membrane: (A) is a polyether, polytetramethylene oxide, polymethylene, octamethylene or water retentive resin (E) which is a polyethylene oxide (preferably a mixture of polytetramethylene oxide and polyethylene oxide). (E) has less than 4C connected in series in the chain. (B) is formed by a silicon-oxygen bond. (D) (1 - 60 wt.% based on the whole proton conducting membrane).which is glass fibers.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: (A) and hydrolyzable inorganic compound which forms (B) are mixed with each other in an organic solvent (G). (G) is further incorporated with a compound (H) selected from ethylene carbonate, propylene carbonate or butylene carbonate. (H) has a relative dielectric constant of at least 20 and boiling point of at least 100 degreesC.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: (B) is formed by a silicon-oxygen bond and (C) is an inorganic solid acid (preferably tungstophosphonic acid). (C) (5 - 500 wt. parts) per 100 wt. parts of (A) and (B).    TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Materials: The membrane additionally comprises reinforcing agent (F). EXAMPLE - Polytetramethylene glycol 650 (weight-average molecular weight:650) (75 g) was put in a dried glass container to which KBE-9007 (3-triethoxysilyl propyl isocyanate) (57.1 g) was added. The mixture was slowly agitated at 60 degreesC for 120 hours in a nitrogen atmosphere. The obtained viscous liquid was tested and spectral pattern, reasonably considered to be relevant to a polytetramethylene oxide with triethoxysilyl groups at the terminals was observed. The obtained product polytetramethylene oxide (A) with triethoxysilyl group at the terminals was pure and had the silicon atoms derived from the hydrolyzable silyl group (triethoxysilyl group) at 4.9 wt.%.    (A) (1 g) was dissolved in isopropanol (1 g). Tungstophosphoric acid (1 g) was separately dissolved in isopropanol (1 g). These solutions were mixed with each other for 1 minute with vigorous agitation. The mixed solution was put in a Yamamoto MFG (polystyrene petri dish). The dish was put in a container kept at 60 degreesC to which water vapor generated at 70 degreesC and was then heated for 12 hours to obtain a color less, transparent, soft membrane. The content of water was 28 wt.%.    A comparative film was prepared by using Du Pont's Nafion 117 (proton conducting membrane). Both the films i.e. test/comparative had a proton conductivity (S/cm) (at 140 degreesC) of 8.7 x 10 to the power -3/immeasurable because the membrane was deteriorated in properties and broken. The test membrane was soft, did not bend when folded while the comparative membrane was easily broken or decomposed or molten when folded.