414 The Neglect of Chemistry hy Practical Farmers. 



liad calculated the amount of lime present in the 98 per cent, of 

 carbonate of lime. 



Again, to show how a mere analysis of the ash, without giving 

 the proportion of ash contained in the original substance, so far 

 from assisting farmers, may tend much more towards misleading 

 them, I will suppose, for example, that the amount of lime con- 

 tained in the ash of two different plants (A and B), in A was 

 stated at 20 per cent., and in B at only 5 per cent. The farmer 

 here, on casting his eyes over the two analyses, would at once 

 imagine that a crop of the plant A required four times as much 

 lime as one of B ; but if we suppose a given weight of the plant 

 B to contain four times as much ash as the same weight of the 

 plant A, the amount of lime required by equal weights of the two 

 plants would be exactly the same. 



Here, again, we are impressed with tlie necessity of calculating 

 the amount of ingredients contained in a ton, or an average crop 

 of any plant per acre ; for though equal w eights of the two plants 

 in question may contain an equal amount of lime, yet the produce 

 of B per acre may be ten times as large as that of A, and there- 

 fore would require ten times as much lime as A, although the 

 iirst impression, caused by an inspection of the analyses of their 

 ash, was, that A would require four times as much as B. 



These cases must not be considered as merely imaginary or 

 rare exceptions, for I have in my own experience often found 

 farmers falling into these errors. 



I believe that heretofore no one has attempted to lighten the 

 labour of calculation necessary to reduce the results as published 

 to a form in which they may be of practical service to the farmer, 

 if we except the Table on the constituents of crops, compiled by 

 Dr. Daubeny, from ' Analyses ' by Sprengel, and published in a 

 former volume of this Journal. This is the more to be deplored, 

 for the labour, not to mention the expense, that is required to 

 pursue any inquiry to a satisfactory conclusion is so great, that 

 one can scarcely be astonished to find that many a farmer, who 

 may have had his curiosity excited by some exceptional occur- 

 rence, should afterwards relinquish the prosecution of it on 

 account of this very difficulty, particularly when we remember 

 their proverbial distaste for calculation. I have now briefly 

 noticed the causes which appear to me to exert the greatest 

 influence in retarding the spread of the study of chemical agri- 

 culture among farmers ; and in the following pages I purpose 

 inquiring how far it may be in our power to provide remedies 

 for this existing state of affairs with the materials at our com- 

 mand. 



