TABLE _of the Combinations of the Oxalic Acid, with the Salifiable Bases, in the Order of Affinity(A)._ _Bases._ _Neutral Salts._ Lime Oxalat of lime. Barytes barytes. Magnesia magnesia. Potash potash. Soda soda. Ammoniac ammoniac. Argill argill. Oxyd of zinc zinc. iron iron. manganese manganese. cobalt cobalt. nickel nickel. lead lead. copper copper. bismuth bismuth. antimony antimony. arsenic arsenic. mercury mercury. silver silver. gold gold. platina platina. [Note A: All unknown to the ancient chemists.--A.] SECT. XXXII.--_Observations upon Oxalic Acid, and its Combinations._ The oxalic acid is mostly prepared in Switzerland and Germany from the expressed juice of sorrel, from which it cristallizes by being left long at rest; in this state it is partly saturated with potash, forming a true acidulous oxalat of potash, or salt with excess of acid. To obtain it pure, it must be formed artificially by oxygenating sugar, which seems to be the true oxalic radical. Upon one part of sugar pour six or eight parts of nitric acid, and apply a gentle heat; a considerable effervescence takes place, and a great quantity of nitrous gas is disengaged; the nitric acid is decomposed, and its oxygen unites to the sugar: By allowing the liquor to stand at rest, cristals of pure oxalic acid are formed, which must be dried upon blotting paper, to separate any remaining portions of nitric acid; and, to ensure the purity of the acid, dissolve the cristals in distilled water, and cristallize them afresh.