MATERIALS, CONSISTING OF PENETRATING LIQUIDS-NAMELY, AQUEOUS ELECTROLYTES CONTAINING A WETTING AGENT; CONCENTRATES-NAMELY, CONCENTRATED PENETRATING LIQUIDS FOR DILUTION WITH WATER BEFORE USE; AND INDICATING POWDERS-NAMELY, INORGANIC OR MINERAL POWDERS FOR USE IN LOCATING CRACKS, LEAKS, OR OTHER DEFECTS IN FIRED CERAMICS, PORCELAIN ENAMELS, GLASS, GLAZED CHINA, PLASTICS, AND OTHER NON-CONDUCTING MATERIALS