cool, in the beaker. Half a test-tubeful of the "Magnesia 

 Mixture" is added, and the beaker left covered in a cool place. 

 Next day (z>., at least 12 hours afterwards), the crystalline 

 precipitate in the beaker is collected on a Swedish paper, 

 washed with rather strong Ammonia water, dried in the water- 

 oven, collected in the usual way in a weighed crucible. The 

 filter-paper is ignited white, and added to the precipitate. 

 The crucible is then ignited, first on the Bunsen flame and 

 afterwards before the Blow-pipe flame for five minutes. It is 

 left in the desiccator to cool, and afterwards weighed. The 

 increase of weight of the crucible is due to the Magnesium 

 Phosphate formed in combination with the total phosphoric 

 acid in one gram of Super, the usual weight of paper ash 

 being allowed. 



(6) CaH \P^O 8 . Five grams of the well-mixed sample 

 of Super are weighed out on a watch glass. Half a litre or 

 500 c. c., of distilled water is measured out into the wash- 

 bottle, previously completely emptied. This water is used for 

 the process of mixing up the Super with water. The mixing 

 is done in the following way : The 5 grams of Super are 

 transferred, with the help of a feather finally, into a clean and 

 dry mortar. The outside of the lip of the mortar is rubbed 

 with a little grease to ensure the running out of all the 

 water from the mortar to the Green bottle. The Super is then 

 rubbed smooth with the pestle, a little water being added to 

 it from the wash-bottle. Great care should be taken that none 

 of the water in the wash-bottle might be wasted or spilt out- 

 side the mortar. The mixture is then left undisturbed for a 

 few minutes, and the supernatant liquid is drained off care- 

 fully from the mortar along a clean and dry glass rod into a 

 clean and dry green stoppered bottle. The green-bottle is 

 used as that glass is not attacked by Phosphoric acid. As a 

 further security against loss of water a funnel is placed on the 

 bottle, and the water drained down on the funnel. The opera- 

 tion of rubbing the Super and a further quantity of water is 



