512 PROCEEDINGS OF THE CHEMICAL DEPARTMENT. 



taining 037 of potash, and 0-051 of phosphoric acid, like Mr 

 Mustard's, to one containing a trace of phosphoric acid and 

 0165 of potash, like Mr Mcoll's ; and yet the unmanured soil in 

 the latter case yields 8 tons 9 cwt. of crop, and the former only 

 1 ton 6 cwt. The natural capability of Mr Mcoll's soil, not- 

 withstanding the comparatively small quantity of these two 

 matters, is the larger. But when they are manured, this difference 

 disappears, for on the naturally poorer soils manures produce by 

 far the largest effect. A mixture of superphosphate and sul- 

 phate of ammonia raises the produce of Mr Mustard's soil from 

 1 ton 6 cwt. to 13 tons 8| cwt., or by 12 tons 2| cwt., while 

 exactly the same application brings Mr Mcoll's up from 8 tons 

 9 cwt. to 13 tons 14 cwt., giving an increase of only 5 tons 5 

 cwt., or less than half of the former. Such facts are most in- 

 structive to the agricultural experimenter, for they teach him to 

 be cautious, and prevent his drawing conclusions from too 

 limited a series of experiments. Indeed, there is no conclusion 

 that forces itself more strongly on his mind than the necessity of 

 gathering together a very large number of experiments before he 

 attempts to draw conclusions from them at all. Unfortunately, 

 the opposite course is that too often adopted. A single experi- 

 menter makes some experiments, and from their results he con- 

 siders himself entitled to draw conclusions applicable to all 

 possible conditions, an inference which the facts by no means 

 justify. Uncalculable injury has been caused in this way to the 

 progress of scientific agriculture, and until experiments are 

 sufficiently multiplied, no good results can be obtained. The 

 experimenter, in place of rushing to conclusions, must endeavour 

 to exercise a degree of patience which is often very trying. It 

 is this course which we are endeavouring to pursue in regard to 

 our field experiments, and to avoid drawing conclusions which 

 the results of another season may upset. Not adhering to this is 

 the cause of the numerous conflicting results which are found in 

 the records of experimental agriculture, results which might 

 have been reconciled, had similar experiments been continued 

 sufficiently long to eliminate differences which might thus have 

 been easily explained, but which, from the absence of this pre- 

 caution, are now hopelessly irreconcilable. 



Field Experiments of 1868. 



It was intended to have published now the field experiments 

 of 1868, but the late period at which some of the results have 

 been obtained from the experimenters, has made it entirely im- 

 possible to do justice to them without delaying the publication 

 of the Transactions. This course, however, having been con- 

 sidered inadvisable, I am reluctantly compelled to postpone 

 them for the present. 



