244 APPENDIX. 



ANALYSES OF THE ASHES OF SOME PLANTS, 



BY DE SAUSSURE. 

 CHEMICAL. INQUIRIES INTO VEGETATION. LEIPZIG, 1805. 



The method of analysis employed by De Saussure consisted of the 

 following : 



A. The ashes were treated with water, and the parts soluble in it were 

 introduced into. the calculations, in the second and following columns. 



B. The residue remaining undissolved in the last operation was dis- 

 solved in nitric acid, and evaporated to dryness ; the portion now insolu- 

 ble in water was silica. 



C. By precipitating the solution obtained in B, with prussiate of pot- 

 ash, the iron and manganese were obtained, the amount of iron supplied 

 by the re-agent being subtracted in the calculation. 



D. By a further precipitation of the solution with ammonia, the earthy 

 phosphates were obtained (lime and magnesia). 



E. By treating this precipitate with caustic potash, neutralizing it 

 with an acid, and precipitating it with ammonia, the earthy phosphates 

 mixed with alumina (phosphate) were procured. 



F. By a further precipitation of the liquid D with carbonate of soda, 

 and, by continued boiling, the earthy carbonates were obtained. 



G. The difference of the products of these different operations, when 

 compared with the total weight of the ashes analysed, expressed the few 

 per cent, loss ; and the quantity of salts with alkaline bases which were 

 not dissolved by the first treatment with water. 



According to the second mode of procedure, which Saussure considers 

 to be the most exact, the ashes, containing alkaline phosphates, were 

 chiefly analysed. 



The ashes were dissolved in nitric acid, the lime and magnesia sepa- 

 rated as phosphates, the liquor evaporated to dryness, and heated to red- 

 ness with the addition of charcoal. 



The residual salts were now saturated with acetic acid, dried and 

 treated with alcohol ; the phosphates and sulphates of potash, and chloride 

 of potassium, were left behind. 



