304 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



From these figures, reduced by means of the critical constants, Ter 

 Gazarian finds PHg^ 33.931. The probable error is 0.0012. Hence P = 

 30.908. 



Baxter and Jones ' based their determinations of the atomic weight of 

 phosphorus upon analyses of silver phosphate. This salt, was dissolved, 

 and the silver precipitated and weighed as bromide, and in one experi- 

 ment as chloride. 



The weights, in vacuo, and the ratios are as follows: 



Ag,PO,. 

 6.20166 

 6.35722 

 5.80244 

 5.05845 

 7.15386 

 7.20085 

 6.20182 

 5.20683 



AgBr. 



8.34490 



8.55419 



7.80819 



6.80685 



9.62694 



9.68947 



8.34522 



7.00605 



Ratio. 



134.558 



134.559 



134.567 



134.564 



134.570 



134.560 



134.561 



134.555 



Hence P= 31.051. 



Mean, 134.562, ± .0012 



AgsPO,. 

 3.34498 



AgCl. 

 3.43544 



Ratio. 

 102.704, 



.0034 



Hence P= 31.054. 



The probable error assigned to the last ratio is that of one experiment 

 in the bromide series. 



From the following ratios the atomic weight of phosphorus is now 

 to be computed. 



(1). 2P:PA: : 1.0: 2.28955, ± .00032 

 (2). 3Ag:PCl3::100:42.4553, ± .0036 

 (3). 5Ag:P: :100:5.7322, ± .0045 

 (4). AgsPO^ : 3 Ag :: 100: 77.313, ± .0088 

 (5). Ag„P0,:3AgCl: : 100: 102.704, ± .0034 

 (6). Ag3P04:3AgBr: : 100: 134.562, ± .0012 

 (7). PHs = 33.931, ± .0012 



To reduce these we have — 



Ag =107.880, ± .00029 

 CI = 35.4584, ± .0002 



Br = 79.9197, ± .0003 

 H = 1.00779, ± .00001 



1 Joum. Atnei-. Chem. Soc, 32, 298. 1910. 



