Manganese as the Pyrophosphate. 



239 



In this series of determinations the amount of ammonium 

 chloride present was constant while the volume of the liquid 

 present was varied and the amounts of the microcosmic salt. 









Table 



III. 









Mn 2 P 2 7 

 equivalent to 

 MnCl 2 . 



Taken. Found. 



Error 

 in terms of 

 Mn 2 P 2 7 . 



Error in 



terms of 



Manganese. 



Saturated 

 solution of 



HN T aNH 4 

 P0 4 .4H 2 0. 



XH 4 CI. 



Total 

 volume. 



Manga- 

 nese 

 in the 



grm. 



grm. 



grm. 



grm. 



cm 3 .' 



grm. 



cm 3 . 



filtrate. 



0'2214 



0-2202 



0-0012- 



0-0005- 



5 



20 



200 



none 



0-2214 



0-2202 



0-0012- 



0-0005- 



5 



20 



200 



u 



0-2214 



0-2191 



0-0023- 



0-0009- 



5 



20 



200 



c< 



0-2214 



0-2191 



0-0023- 



0-0009- 



5 



20 



300 



(<■ 



0-2214 



0-2191 



0-0023- 



• 0-0009- 



5 



20 



300 



a 



0-2214 



0-2185 



0-0029- 



0-0011- 



10 



20 



200 



u 



0-2214 



0-2186 



00028 — 



o-ooio — 



20 



20 



300 



tt 



02214 



0-2192 



0-0022 — 



0-0009- 



20 



20 



300 



a 



These results are possibly a trifle less satisfactory than those 

 obtained for the smaller amounts of manganese by the method 

 of Table II, it may be because the prolonged boiling tends to 

 form a trifling amount of free oxide; but the fact is disclosed 

 that an increase of the microcosmic salt is without influence 

 and that a variation in volume from 200 cm3 to 300 cm3 is the 

 occasion of little change in the indications of the process. 



In another series of experiments the solution of inanganous 

 chloride was added drop by drop to the mixture of microcosmic 

 salt and ammonium chloride made alkaline with ammonia. 

 The precipitate which fell in the cold was crystallized by boil- 

 ing the mixture a few minutes. The results are given below : 



Table IV 



Mn 2 P 2 7 













equivalent to 













MnCl 2 . 



Error in 



Saturated 









A 



terms of solution of 

 Error. Maugauese. HNaN"ET 4 P0 4 . 





Total 

 volume 



Manga- 

 . nese in 



Taken. Found. 



N1I 4 C1. 



grm. grm. 



grm. grm. 



cm 3 . 



grm. 



cm 3 . 



filtrate. 



0-1542 0-1521 



0-0021— 0-0008 — 



5 



5 



200 



none 



0-2214 0-2203 



0-0011— 0-0004 — 



5 



10 



2 75 



c« 



0-2214 0-2192 



0-0022— 0009 — 



5 



15 



275 



(( 



0-2214 0-2197 



0-0017— 0-0007 — 



5 



20 



2 75 



«c 



02214 0-2223 



0-0009 -f 0-0003 + 



5 



20 



200 



a 



01542 0-1528 



00014— 0-0005 — 



5 



30 



275 



ct 



The experience of this series of experiments demonstrated 

 again that the ease with which the flocky precipitate is con- 

 verted to the crystalline ammonium manganese phosphate is 



