190 On Tribune Phosphoric A 



meanPO, 3.V17 

 Fe s O, 35.23 

 IMJ 29.45 



100.15 

 We see that it is Impossible by this method to separate .ill 

 the phosphoric acid from the iron, as I will hereafter show by 

 direct analysis. 



VTI. Fusing Method. (In connection with J\10„.) 



The following analyses were made with a view of ascertain- 

 ing the influence which alkaline salts exert on the ammonio- 

 phosphate of magnesia. To this end, the analyses were 

 conducted in exactly the same way as heretofore described, 

 with the difference only thai the PO B after having acidu- 

 lated the filtrate with nitric acid, was first precipitated by 

 molybdic acid solution. The residue of iron was dissolved in 

 IK'l. and precipitated by Nil and Nil s. After washing out, 

 the sulphide of iron was again dissolved, oxydized, and pre- 

 cipitated by ammonia. The results go 1" bIiow that the 

 alkaline salts dissolve more of the am m on io-phosphate of mag- 

 nesia than ammoniacal water alone, and that sulphide of iron 

 is Boluble, to Borne extent, in poly-6ulphide of ammonium. 



The results are as follows : 



(a)— 0.2951 (b)— 0.271 (c)— 0.4302 



PO 35.63 l:» 35.8J 



I'e <) 34.29 34.35 34.22 



No 30.08 30.16 29.97 



mean 1 '< > 35.64 



Fe.0,34.29 

 Mo 30.07. 

 It i- needless for me t<> state, thai all the analyses jusl cited 

 made with the greatest care. The results "I' each method 

 agree bo well, that we have to look for the differences to errors 



