hydrate is soluble in NH 4 HO. Therefore the excess of NH 3 

 should be got rid of by leaving the beaker uncovered in 

 the sand-bath for a little while. The abundant reddish brown 

 jelly like precipitate contains all the Phosphorus pentoxide 

 with Fe 2 O 3 ,Al 2 O 3 etc. ; and the filtrate, the Potassium and 

 the Lime. The precipitate on the filter-paper is thoroughly 

 washed with hot water. 



(6) Lime. The filtrate and washings are boiled, and 

 treated with Ammonium oxalate, as long as precipitate is 

 produced. The whole is filtered and washed, till the wash- 

 ing shows no trace of K, tested with a platinum wire on the 

 flame. The residue is left in the water-oven to dry, to 

 be afterwards ignited gently and weighed as CaCO 3 . 

 To avoid the difficulty of burning a lime precipitate, it is 

 best to sulphate the precipitate, i. e. } drive off the CO 2 by 

 igniting the precipitate in blow-pipe flame and then add a 

 little dilute H 2 SO 4 . The precipitate should be then dried 

 on vapour-bath, ignited gently over Argand flame, then 

 thoroughly over blow-pipe flame to get CaSO 4 . The pro- 

 portion of CaO may be inferred from that of CaSO 4 found 

 out. The filtrate and washings are left uncovered in the 

 sand-bath to dry. The dry residue is transferred to a clean 

 porcelain bason, and gently ignited in it. The fragments 

 adhering to the sides of the beaker are washed out into the 

 porcelain bason when it is cool after the ignition. This is 

 left on the steamer to dry. When dry, it is ignited again, in 

 the same way, gently to drive off all ammonia-salts. Pure 

 oxalic acid is then added to the bason when cool, to dissolve 

 the bases (K and Mg), some water added, the whole dried 

 on the steamer, and again gently ignited. The residue is 

 dissolved in hot water, and filtered. The clear filtrate and 

 washings are treated with HCl in slight excess, transferred to 

 the porcelain bason, and left on the steamer to dry. It is 

 again gently ignited. The residue is dissolved in a little 

 water, one-third of a test-tube full of platinum tetrachloride 



