)0'3 SMITII80XIAX :mt8celi.axeous collections vol. 54 



PHOSPHORUS. 



The inatfrial I'roin which to calciilate the atomic weight of i)liosphorus 

 is by no means abundant. Bcrzelins, in bis LfliTl)ueh,^ adduces only bis 

 own experiments npon tbe precipitation of gold by phospliorus, and ig- 

 nores all the earlier work relating to the composition of tbe phosphates. 

 These experiments liavc been considered with reference to gold. 



PelouTie/ in a single titration of phosphorus trichloride with a standard 

 solution of silver, obtained a wholly erroneous result ; and Jacquelain/ in 

 his similar experiments, did even worse. Schrotter's criticism upon 

 Jacquelain sufficiently disposes of the latter." 



Only the determinations made by Schrotter, Dumas, Van der Plaats, 

 Ter Gazarian and Baxter and Jones remain to be considered. 



Schrotter^ burned pure amorphous phosphorus in dry oxygen, and 

 weighed the pentoxide thus formed. One gramme of P yielded PoO., in 

 the following proportions : 



2.28909 



2.28783 



2.29300 



2.28831 



2.29040 



2.28788 



2.28848 



2.28856 



2.28959 



2.28872 



Mean, 2.28918G, ± .00033 



Hence P = 31.02?. 



Dumas" prepared pure phosphorus trichloride by tbe action of dry 

 clilorine upon red phosphorus. The. [portion used in his experiments 

 boiled between 76" and 78°. This was titrated with a standard solution 

 of silver in the usual manner. Dumas publishes weights, from which I 

 calculate the figures given in tbe third column, representing the (juantity 

 of trichloride proportional to 100 parts of silver: 



' 5th ed., 1188. 



"Compt. Rend., 20, 1047. 



^Conipt. Rend., 33, 693. 



* Journ. prakt. C'heni., 57, 315. 



"Joum. prakt. Chem., 53, 435. 1851. 



«.\nn. Chem. Pharm., 113, 29. 1860. 



