DELPHIAN

ELECTRONIC INSTRUMENTS--NAMELY, (( AUTOMATIC PORTABLE PH METERS FOR USE IN MEARURING THE ACIDITY OR BASICITY OF AQUEOUS LIQUIDS; )) HYDROGEN SULFIDE DETECTORS FOR USE IN MEASURING IONIC AND GASEOUS CONCENTRATIONS IN AQUEOUS LIQUIDS; PLATINUM WIRE SENSORS FOR USE IN MEASURING THE CONCENTRATION OF VARIOUS GASES IN THE AIR