<^ the fecundating Dust of the Date Tree. 57 



water, that the portion not dissolved in this liquid was phos-r 

 phate of lime. It became necessary to know the real nature 

 of the portion dissolved by the water ip the experiment last 

 described. This aqueous solution, mixed with ammonia, 

 gave a very abundant precipitate of a yellowish white colour, 

 like gelatine, which, when well washed and dried, we>ghe4 

 pne gramme and one-fifth, or twelve decigrammes. 



This precipitate was melted into a transparent pearl hy the 

 blow-pipe J it exhaled a strong smell of ammonia, and spar- 

 kled during its fusioii with a very distinct phosphoric light, 

 A boiling ley of caustic potash liberated from it the smelj 

 of ammonia, diminished it in yolunie, and gave it the forrq. 

 of a light flaky substance : the filtered filkaline liquor, satu- 

 rated with nitric acid and boiled for a few minutes, gave by 

 means of lime- water a verv abundant precipitate, which 

 was recognised to be calcareous phosphate. Thur, the pre- 

 cipitate formed in the aqueous solution by ammonia cou-r 

 tained phosphoric acid : we afterwards ascertained the base tq 

 .which this acid was united, by the following experiments: 



The light flakes, separated by the potash which had 

 taken up the phosphoric acid, were of a yellow colour, 

 of the consistence of pasle, and became h^rd when dried. 

 Sulphuric acid dissolved them almost entirely, exceplino' 

 a little sulphate of lime which was formed; and this solu- 

 tion filtered, and left to evaporate, spontaneously presented, 

 3;i a fe\v days, prismatic crystals, the taste, solubility, antj 

 properties of which were perfectly similar to those of the 

 sulphate of magnesia. The pollen of the date tree therefore 

 pontains magneslan phosphate, like several other animal 

 substapces. 



§ VI. Examination of the Matter fiom ivhich the P/iosphafe 

 of Magnesia was separated by Ammonia. 

 The aqueous solution pf the extract of pollen treated at 

 first by alcohol, deprived by the addition of ammonia of the 

 magnesian phosphate which it contained, h,Hving been eva-r 

 porated to the consistence of a clear syrup, furnished, upon 

 cooling, a granulous mass filled with small transparent and 

 prisraalic crystals, f^ils sal^ was a combination of malicr 



acid' 



