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ent in the one gram of Super, the usual allowance of '002 

 grams being, of course, made for the ash of the filter- 

 paper. 



(4) Lime. The filtrate and washings from the Siliceous 

 matter in one gram of Super, are treated with a few drops 

 of dilute Ammonium Hydrate, with constant stirring, until a 

 permanent opalescence is just produced. A few drops of 

 Oxalic acid are then added which for a moment clear the 

 solution. Ammonium oxalate is then added, with constant 

 stirring, until it ceases to produce any more precipitation. 

 The beaker is then left covered up in the sand-bath over- 

 night for the Calcium oxalate to collect at the bottom. Next 

 day the Calcium oxalate precipitate is collected on a Swedish 

 paper, and the filtrate containing all the phosphates, collected 

 under the filter on a clean beaker. The precipitate is tho- 

 roughly washed with hot water, dried in the water-oven, and 

 next day collected in a weighed Platinum crucible, the white 

 ash of the filter-paper being also put into it. The crucible is 

 ignited on very low heat, for about a quarter of an hour, to 

 convert the CaC 2 O 4 into CaCO 3 , but not into CaO. It is 

 cooled in the desiccator, and weighed. The increase of 

 weight of the crucible is due to the Calcium carbonate (com- 

 monly, but inaccurately, called Lime) present in one gram 

 of the Super, the usual allowance for the paper ash being 

 made. 



(5) Total Phosphates. -The filtrate and washings, 

 from the lime precipitate, are concentrated to about 60 c. c. 

 by boiling them in a beaker. When cool, a tea spoonful of 

 Citric acid is added, and then to avoid diluting the contents 

 of the beaker, a few drops of very strong Ammonium Hydrate 

 are added, until the liquid becomes distinctly ammoniacal. 

 Usually no precipitate follows. If a precipitate immediately 

 follows, it would indicate the presence either of lime, iron, or 

 alumina. The next step, viz., the addition of Magnesium 

 Sulphate solution, should be taken when the liquid is quite 



