1846.] Analysis of Soils. 231 



and iron. Collect them on a filter; wash and dry them. Then 

 by means of the blowpipe, with boracic acid and a fine steel wire 

 ascertain if phosphoric acid is present by forming a phosphorate 

 of iron, which is a white brittle substance. (See Berzelius on 

 the Blowpipe.) 



Take another portion of the solution, and precipitate the per- 

 oxide of iron, by means of a boiling solution of pure potash. 

 Collect the per-ox. iron, &c., on a filter, wash the precipitate, 

 and then re-dissolve it in chlorohydric acid, and add a considera- 

 ble excess of acid. Then add ammonia until the solution is satu- 

 rated and is of a red color, and a little per-oxide of iron is pre- 

 cipitated. Then add a solution of neutral succinate of ammonia, 

 which will precipitate all the per-oxide of iron as a succinate. 

 Filter and wash very slightly with w^ater containing a little am- 

 monia. To the filtered solution rendered neutral add a solution 

 of carbonate of potash and carbonate of manganese will be pre- 

 cipitated as a white precipitate, which collect on a filter; wash, 

 di y and examine by means of the blowpipe and tests. The alka- 

 line solution of alumina may be treated as described under the 

 head of analysis of the insoluble silicates. 



By working on a sufficient quantity of the precipitate, the pro- 

 portions of phosphoric acid, ox. manganese and alumina may be 

 accurately determined by the above described method. And an 

 approximation may be made by dividing even the 5 grains of 

 precipitate, and working on the parts for each of the above men- 

 tioned ingredients. 



In searching the soluble matters for alkalies, we omit precipi- 

 tatiftg the magnesia by phosphate of soda, and take the solution 

 from which we have thrown down the lime and evaporate it to 

 dryness and expel the ammoniacal salts. We have then only the 

 chlorides of the alkaline metals and manganese present, which are 

 separated by treating the solution with black oxide of mercury, 

 and boiling so as to throw down the magnesia. Then the filtered 

 solution will give by evaporation and a red heat in a platina 

 capsule the chlorides of sodium and potassium, which are to be 

 separated by chloro-platinic acid as before described. 



