56 PROCEEDINGS OF THE AMERICAN ACADEMY 



I. 



Two portions of 20 cm 8 each of a solution of hydro-disodic phos- 

 phate were evaporated to dryness, and the residue was ignited and 

 weighed as sodic pyrophosphate. 



(1) g<*ve of Na 4 P 2 7 0.1217 gr. 



(2) „ „ 0.1214 gr. 



The solution contained, therefore, 0.1298 gr. of P 2 5 to every 40 cm 8 . 



II. 



A quantity of microcosmic salt was recrystallized, dried between 

 papers by pressure, and the amount of loss on ignition determined in 

 two portions. 



(1) 1.1419 gr. gave of NaP0 8 0.5836 gr. = 51.11 % 



(2) 0.9846 gr. „ „ 0.5027 gr. = 51.06$ 



Of this salt 3.7583 gr. were dissolved in water and the solution 

 diluted to one litre. The solution contained, therefore, 0.0512 gr. of 

 P 2 5 to every 40 cm 3 . 



III. 



The solution contained hydro-disodic phosphate. 



(1) gave Na 4 P 2 7 from 40 cm 3 0.3490 gr. 



(2) „ „ „ „ 0.3490 gr. 



Every 40 cm. 8 contained, therefore, 0.1863 gr. P 2 6 . 



IV. 



The solution contained hydro-disodic phosphate. 



(1) gave Na 4 P 2 7 from 40 cm. 8 0.3530 gr. 



(2) „ „ „ „ 0.3533 gr. 



Every 40 cm. 8 contained, therefore, 0.1885 gr. P 2 5 . 



V. 



The solution contained hydro-disodic phosphate. 



(1) gave Na 4 P 2 7 from 40 cm. 8 0.3512 gr. 



(2) „ „ „ „ 0.3514 gr. 



Every 40 cm. 8 contained, therefore, 0.1875 gr. P 2 5 . 



