Method of and means for the rapid approximate quantitative estimation of chloride concentration in aqueous liquids

Claim 1

METHOD OF MAKING AN INDICATOR ARTICLE FOR RAPIDLY CONDUCTING THE APPROXIMATE QUANTITATIVE ESTIMATION OF CHLORIDE CONCENTRATION IN URINE BY THE BLEACHING OF THE INDICATOR AND WHEREIN THE TIME TAKEN TO BLEACH THE INDICATOR IS RELATED TO THE CHLORIDE CONCENTRATION IN THE URINE BEING TESTED, WHICH METHOD COMPRISES IMPREGNATING A WATER-ABSORBENT FIBROUS CELLULOSIC MATERIAL WITH AQUEOUS SOLUTION CONTAINING SILVER CHROMATE DISSOLVED IN DILUTE AMMONIUM HYDROXIDE, TREATING THE IMPREGNATED MATERIAL WITH A DILUTE ACID FREE OF CHLORIDE THEREBY TO PRECIPITATE SILVER CHROMATE ON TO THE FIBRES OF SAID MATERIAL, AND DRYING THE MATERIAL SO IMPREGNATED, SAID DRIED MATERIAL HAVING SUCH AN AMOUNT OF SILVER CHROMATE DEPOSITED THEREIN AND ALSO HAVING SUCH A WATER-DIFFUSION RATE THERETHROUGH THAT SAID MATERIAL IS BLEACHED WITHIN ANY OF THE FOLLOWING PERIODS OF TIME MEASURED AGAINST THE FOLLOWING CORRESPONDING CONCENTRATIONS OF SODIUM CHLORIDE BY WEIGHT IN AQUEOUS SOLUTION AT 20* C.; UPON CONTACTING THE MATERIAL WITH A SAMPLE OF URINE.