of certain Soils and Waters in Belgium. 39 



manent precipitate. A quantity ofperchloride of iron was then 

 added, and acetate of potash, until a deep wine-red colour was 

 produced ; the liquor was then boiled until all odour of acetic 

 acid ceased, and a copious brown precipitate formed, which 

 was separated by the filter. This precipitate was then re- 

 dissolved in muriatic acid, boiled until all odour of acetic acid 

 ceased, and the liquor then precipitated by ammonia. The 

 precipitate, collected on a filter, was dried, ignited, and weighed, 

 then redissolved by muriatic acid. A quantity of tartaric acid 

 was added to the liquor, and ammonia then added in such 

 excess as to redissolve the precipitate which first forms. To 

 the solution thus got, hydrosulphuret of ammonia was added 

 in excess, the sulphuret of iron collected on a filter, and, when 

 washed, redissolved in aqua regia. The peroxide of iron, 

 precipitated from the liquor by ammonia, collected, dried, 

 ignited and weighed, and its weight subtracted from the weight 

 of the basic phosphate previously given, determines in an ab- 

 solute manner the quantity of phosphoric acid. 



To the liquor from which the phosphoric acid had been 

 separated by the means described above, hydrosulphuret of 

 ammonia was added, by which a precipitate was formed, which 

 was collected, and, while moist, boiled with caustic potash 

 liquor; the undissolved matter was dissolved in muriatic acid 

 nearly neutralized, and treated with benzoate of ammonia ; by 

 this a trace of iron, generally remaining from the preceding 

 process, was removed, and the manganese was then precipi- 

 tated by carbonate of ammonia, collected, ignited and weighed. 

 The potash liquor was then acidulated by muriatic acid, and 

 the alumina which it had dissolved was precipitated, and its 

 quantity detei'mined in the usual way. 



The solution, from which the iron, alumina, and manga- 

 nese had thus been separated by hydrosulphuret of ammonia, 

 was next boiled until all odour of sulphuretted hydrogen 

 ceased, and then treated with oxalate of ammonia, the oxalate 

 of lime collected was gently ignited with carbonate of ammonia, 

 and the quantity of lime determined. The liquor was then 

 very much concentrated by evaporation, and treated with 

 phosphate of soda and ammonia, set aside until the ammoniaco- 

 magnesian phosphate had perfectly deposited, and the quan- 

 tity of magnesia determined from that of the latter salt. 



The third portion of the ash liquor was treated with nitric 

 acid, so as perfectly to peroxidize the iron ; it was then de- 

 composed by chloride of barium, by which all the sulphuric 

 acid was separated as sulphate of barytes, collected and weighed. 

 To the filtered liquor there was added a great excess of phos- 

 phate of soda and ammonia, and then an excess of acetic acid. 



