t 



428 The Neglect of Chemistry hy Practical Farmers. 



plants, however, is considered very doubtful bj chemists ; the 

 second occurs only in very minute quantities, and is often dis- 

 regarded ; whilst the third, carbonic acid, being really an organic 

 compound, is only inserted because it is always present in the 

 ash whenever any organic acids existed in the plant previous to 

 combustion, and therefore becomes necessary to be taken into 

 account, in order that the correct amount of the other ingredients 

 may be determined. 



I have adopted the plan of Professor Way, resolving the salts 

 into their proximate elements in those analyses where a different 

 arrangement had been adopted, as by giving the amount of each 

 individual element a comparison between any two analyses can be 

 instituted at once. It must not, however, be supposed that the 

 elements exist in this isolated condition in the ash of plants, for 

 the acids mentioned are always combined with the alkalies, or 

 earths, in which form they are commonly termed salts of the earth, 

 or alkali. The silica, or as it is often named silicic acid, is also 

 generally found in combination with an alkali and earths. 



Total Sulphur. — This column has been inserted on account of 

 a late discovery by Professor Way, that in the act of burning sub- 

 stances for the purpose of analyses, in some instances a large 

 amount of sulphur was found to have been dissipated, but as the 

 means employed for ascertaining its amount before combustion are 

 inadequate to determine the state in which it existed in the 

 substance, whether as wholly sulphuric acid or in part free 

 sulphur, it became necessary to state the result under the latter 

 head. (I may here mention that dry sulphuric acid contains 40 

 per cent, of sulphur.) It follows, then, from the above fact, that 

 all the analyses in these tables that are not corrected for this loss 

 of sulphur are erroneous in that respect, and it certainly must be 

 considered as fortunate if this, the only error that Professor Way 

 could detect, be the only real error ; for if phosphorus, in the 

 state of phosphoric acid, were acted upon in the same way by 

 heat, which Professor Way does not think is the case, it would 

 cause one of the most important columns to the practical farmer 

 to become utterly valueless. 



It must particularly be remembered, in using these tables, that 

 this column is in addition to the remaining constituents of the 

 ash, except that it includes the sulphur of the sulphuric acid men- 

 tioned there. It is calculated from the ichole plant, and therefore 

 it must not be imagined that the ash left by burning contains that 

 percentage of sulphur. 



In Part I. of each of these tables, for instance, the quantity of 

 sulphur stated under this head is the amount contained by the 

 whole plant, or part of a plant, when dried at 212° F., supposing 

 none to be lost in the operation of drying, and not in 100 



