THE ASH OF PLANTS. 173 



In the older analyses of other classes of agricultural 

 plants, especially in root crops, similarly great variations 

 occur. 



Some uncertainty exists as to these older data, for the 

 reason that the estimation of soda by the processes custom- 

 arily employed is liable to great inaccuracy, especially 

 with the inexperienced analyst. On the one hand, it is 

 not easy, (or has not been easy until lately,) to detect, 

 much less to estimate, minute traces of soda, when mixed 

 with much potash ; while on the other hand, soda, if pres- 

 ent to the extent of a per cent or more, is very liable to 

 be estimated too high. It has therefore been doubted if 

 these high percentages in the ash of grains are correct. 



Again, furthermore, the processes formerly employed for 

 preparing the ash of plants for analysis were such as, by 

 too elevated and prolonged heating, might easily occasion 

 a partial or total expulsion of soda from a material which 

 properly should contain it, and we may hence be in doubt 

 whether the older analyses, in which soda is not mention- 

 ed, are to be altogether depended upon. 



The later analyses, especially those by Bibra, Zoeller, 

 Arendt, Bretschneider, Ritthausen, and others, who have 

 employed well-selected and carefully-cleaned materials for 

 their investigations, and who have been aware of all the 

 various sources of error incident to such analyses, must 

 therefore be appealed to in this discussion. From these 

 recent analyses we are led to precisely the same conclusions 

 as were warranted by the older investigations. Here fol- 

 lows a statement of the range of percentages of soda in the 

 ash of several field crops, according to the newest analyses : 

 Ash of Wheat kernel, none, Bibra, to 5| Bibra. 



" " Potato tuber, 



Barley kernel \ !> u 6[ j yStmann. 



icr ' 7| Zoeller. 



Sno-nrbppt J4.7| Ritthauscn, " 29.8| Ritthausen. 



" et ' 1 5, 7| Bretschneider" m6| Bretschneider. 



Turnip root, 7.7| Anderson, " 17.1| Anderson. 



