56 | | Kaolin | Chalk | Effervescence with dilute acids. | | Water, | Sulphates and | Same as for ammonia. H_{2}O | chlorides | Molec. Wt. 18 | | | Calcium carbonate, | Deposited by boiling. Test as | temporary hardness | for calcium chloride. See | | sodium chloride. | | | Ammonia, almost | Brown coloration, or | always present in | precipitate with Nessler's | distilled and rain | reagent. | water | | | Gelatine | Alum | Ash, sometimes as much as ten | | per cent. | | | Fatty matter | Separated by precipitation with | | alcohol. Dissolved out by ether | | or benzine, and left as a residue | | on evaporation of the solvent. | | | | Ammonium bromide | Potassium bro- | Leaves a residue when heated. (NH_{4})Br | mide or other | Molec. Wt. 98 | non-volatile | | bodies | | | | Ammonium chloride | Same as for chlorides in | | ammonia. | | Pyrogallic acid | Powdered glass | Left behind on solution. | | Potassium iodide | Potassium bromide | The crystals of bromide are | | usually more transparent than | | those of iodide, but no reliance | | can be placed on this. | | Silver nitrate | Potassium nitrate, | Will not yield the full quantity | sometimes present | of chloride on precipitation | in the fused | with HCl. Gives a purple color to | sticks--not in | flame. | the crystals | | | Sulphuric acid | When vended as pure,| No easy test can be given, as the | it invariably | substances are so numerous some of | contains a trace of | them volatile, and most require | iron. Common acid is| separation from the acid before | also liable to | detection.