Abstract: An electrochemical gas sensor is provided, the use of which permits quantitative measurement of volatile gas contaminants in an atmosphere being monitored, generally at ambient temperatures below 100.degree. C. The sensor is constructed of a sensor electrode and a reference electrode on a separator in such a manner as to be exposed to the atmosphere which is sensed for gaseous contaminants. In an alternative embodiment, the sensors can be covered with a selective filter which will selectively allow only small molecule toxic gases to pass for sensing by the sensor electrode while excluding larger interfering gas molecules. In another alternative embodiment, a multiple layer electrochemical gas sensor detects the presence of volatile gas contaminants in a sample gas as well as humidity, temperature, and/or pressure of the gas sample.

Abstract: A compound cross tie for railroad use, the method of making it, and a joiner used therein. The cross tie comprises a pair of wooden end members connected axially by the joiner, and a compressional member traversing the entire assembly: means are provided to prevent relative rotation among the various components.