526 Prof. A. H. Church on certain Ethylphosphates* [Dec. 8, 



gave results, according to the subjoined analytical details, agreeing with 

 the formula 



Fe^-^ 

 Fe^-^ 

 Fe'3 



► 3P04 + 3Aq. 



An identical compound may also be obtained by following the several plans 

 adopted in preparing the ferric ethylphosphate ; it is, however, very diffi- 

 cult to prevent a partial oxidation of the ferrosum in the salt. It will be 

 noted that the atomic weight 28 is indicated by the constitution of this 

 compound. 



In order to analyze the ferroso-ferric ethylphosphate, the following 

 methods were adopted. In a preliminary examination of the salt it was 

 found that strong mineral acids did not effect the separation of phosphoric 

 acid from it : it was also seen that its acid solution gave the ordinary 

 reactions of both conditions of iron. For analysis a weighed amount of 

 the salt was dissolved in dilute sulphuric acid, and the amount of standard 

 permanganate solution decolorized by it ascertained ; this gave the amount 

 of ferrosum in the salt taken. A second experiment was then made, in 

 which the total amount of iron in both forms was determined by perman- 

 ganate after reduction of the sulphuric solution with pure zinc ; the differ- 

 ence between the two percentage results gave the percentage of iron existing 

 as ferricum in the original compound. The numbers thus obtained were 

 on the whole satisfactory ; the total amount of iron agreed nearly with that 

 demanded by theory, though the amount of ferrosum in the salt was never 

 less than '5 per cent, below the required proportion. It was in fact impos- 

 sible entirely to prevent oxidation of the salt ; but it will be perceived that 

 the ferric oxide thus produced, not being lost, introduced but an inconsi- 

 derable error into the determinations. Nor did any inconvenience arise 

 from the presence of phosphovinic acid, which, curiously enough, was found 

 to be without reducing action on the permanganate, even in the presence 

 of sulphuric acid. The following results were obtained in the analysis of 

 the ferroso-ferric ethylphosphate. 



The ferroso-ferric ethylphosphate was dried in vacuo over sulphuric acid. 

 In each experiment with the permanganate solution '5 gramme of the iron 

 salt was taken. Each cubic centimetre of the permanganate solution cor- 

 responded to '00492 grm. of Fe. The following are the results obtained 

 by this method of analysis, three different preparations of the ethylphos- 

 phate being used : — 



Before reduction of the f ^' ^^'^ ^^^^^^^S' Permang. = -070848 Fe 

 ethylphosphate with \ ^^'S cub. centims. permang. = '069864 Fe 



^.^^ ^ ^ III. 14-0 cub. centims. permang. = '06888 Fe 



I IV. 14-4 cub. centims. permang. = '070848 Fe 



After reduction of the) V. 2o'0 cub. centims. permang. = '123 Fe 

 ethylphosphate J VI. 24'6 cub. centims. permang. = '121032 Fe 



