(EP500598-A1)      Method, and appts., for measuring the amount of combustible gas(es) in an atmos. comprises (a) contacting the atmos. with a catalyst for catalysing the combustion of the gas(es); (b) applying a potential difference across a resistance wire that is in thermal contact wth the catalyst so as to catalyst to a temp. at which the combustible gas(es) are combusted; (c) varying the potential difference being applied the resistance wire over time thereby varying the operating temp. of the catalyst; and (d) measuring the change in the electrical resistance of the resistance wire (or a parameter that varies therewith) due to the presence of the combustible gas(es) over at least part of the applied potential range to provide a measure of the amount of combustible gas in the atmos..    ADVANTAGE -   The potential applied across the wire during the course of measurement by a voltage pulse generator (14) is altered, thereby also altering the temp. of the catalyst an it is possible either to resolve the resultant resistance readings into resistance readings for the individual combustible gases or to integrate the resistance readings over time so that the signal produced will be about the same for unit amounts of many combustible gases.    (JP5501917-W)      Method, for measuring the amt. of combustible gas(es) in an atmos. comprises (a) contacting the atmos. with a catalyst for catalysing the combustion of the gas(es); (b) applying a potential difference across a resistance wire that is in thermal contact with the catalyst so as to heat the catalyst to a temp. at which the combustible gas(es) are combusted; (c) varying the potential difference being applied across the resistance wire over time thereby varying the operating temp. of the catalyst; and (d) measuring the change in the electrical resistance of the resistance wire (or a parameter that varies therewith) due to the presence of the combustible gas(es) over at least part of the applied potential range to provide a measure of the amt. of combustible gas in the atmos.    ADVANTAGE -   The potential applied across the wire during the course of measurement by a voltage pulse generator is altered, thereby also altering the temp. of the catalyst and it is possible either to resolve the resultant resistance readings into resistance readings for the individual combustible gases or to integrate the resistance readings over time so that the signal produced will be about the same for unit amounts of many combustible gases.    (EP500598-B1)      A method of measuring the amount of one or more combustible gas in an atmosphere, which method comprises: (1) contacting the atmosphere with a catalyst for catalysing the combustion of said gas, (2) applying a potential difference across a resistance wire that is in thermal contact with the catalyst so as to heat the catalyst to a temperature at which the combustible gas are combusted, and (3) varying the potential difference applied across the resistance wire with time thereby varying the operating temperature of the catalyst correspondingly, (4) measuring the electrical resistance of the resistance wire, or a parameter that varies therewith, due to the presence of the combustible gas in the atmosphere over a range of such potential difference values, (5) deriving from the change in the electrical resistance, or a parameter varying therewith, over the said range of potential difference values, a measure of the amount of combustible gas in the atmosphere, (6) maintaining the catalyst in contact with the atmosphere being monitored throughout the time during which the said resistance changes are measured.