1 v " On Tribasic Phosphoric Acid. 



Fe, 0„ KG has the composition 



62.99 Fe, O, 

 37.01 K< ): 

 Fe, < » ; . K< » Fe I • . 3 EO has the composition 



68.3 - Fe, 3 

 20.17 Ko 

 11.45 IK); while 

 Fe, < I „ £0+2 (Fe, 0„ 3 HO) has the composition 



70.39 Fe, Q, 

 13.78 KO 

 L5.83 IK). 

 approaching very nearly the composition of the substance I 

 analyzed. 



Alter these deviations, I return to my Biibject proper, 

 the following experiments a preparation was used which 

 was produced by pouring a solution of sesquichloride of iron 

 into a solution of phosphate of Boda. After washing oul com- 

 pletely, the precipitate was dried in the air, pulverized, and 

 then pul through a fine sieve to secure more perfect mix- 

 ture. In testing it as to its purity, it proved to be free from 

 Bulphuric and hydrochloric acids, and no traces of alkaline 

 earths could be detected by the spectroscope. The Latter ap- 

 paratus, however, showed a trace of soda. 



I. Dt /< rmination <>j Water. 



For tho determination of water in (a), the powder was dried 

 at ion ( '. and weighed atdifferenl times, afterwards heated to 

 red heat, and weighed again. The mass looked white alter i<>-- 

 nition. In (b) and (c) the Bubstance was imply heated to red- 

 beat and weighed. It looked blue. The results are as follows: 



(a) - 29.99 p. c. Ignited, 

 (b)- 29.99 p. c. 

 (c) 29.98 p. c. " 

 mean— 29.97 p. c " 



