Abstract: An electrochemical gage for measuring partial pressures of oxygen. The gage is preferably in miniaturised form and uses an internal reference or standard of palladium: palladium oxide. The internal reference is disposed in a compartment defined by walls of solid electrolyte.

Abstract: A supplemental printer is mounted piggy-back fashion atop a conventional high speed chain printer or other form of computer output printing equipment; and prints, upon the same print-out sheet as the high speed printer, information generated by the same electronic digital computer to which the high speed printer responds. The supplemental printer is capable of printing postage or other special indicia not easily incorporated into the print symbol repertoire of the high speed printer. In order to make the supplemental printer operate rapidly enough to be compatible with electronic data processing equipment, its print impression is divided into parts printed by individual type segments, each actuated by its own individual print solenoid. Some of the segments are equipped with solenoid-actuated variable numerical print modules for the purpose of printing postage or other variable numerical information.