Vanillalrhodanine was found to be an excellent reagent for silver ions. Its 0.2 percent solution in acetone gives a brownish violet precipitate with silver ions in atnmoniacaI solution. Limit of identification: 0.01_γ. Concentration limit: 1:5,000,000. Merouric and mercurous ions give same reactions, but they can be removed by the addition of aqueous ammonia and the test is to be、carried out in the filtrate, kerric ions, when present in high concentrations, interfere the observation of silver.