108 LETTER-FILES OF S. W. JOHNSON 



few years previously, etc. — " Professor Johnson's 

 method of dealing -with the questions he was present- 

 ing to the agricultural public was to explain scientific 

 processes in a thoroughly scientific way, using the 

 simplest English words, avoiding all technicalities, but 

 making sure that each principle was so clearly set forth 

 that it could easily be understood by any fairly intel- 

 ligent person, however unfamiliar with the subject. 

 Realizing the value of continued reiteration in secur- 

 ing the acceptance of a new idea, he confined himself 

 to insistent repetition of the main facts he was striv- 

 ing to impress on his audience of landowners and 

 farmers. These were : The necessity of employing 

 chemical analysis as the only basis upon which to 

 form an intelligent opinion about the suitable com- 

 position of a fertilizer; the reliability of accurate 

 analyses as a guide to the estimation of value; and 

 the importance to the community of a regular system 

 of analysis of all commercial fertilizers as a safeguard 

 against fraud, as well as against the self-deception of 

 ignorance — ideas which, novel at that time, are now 

 universally accepted and adopted, both by manufactur- 

 ers and consumers, as the basis of the trade in commer- 

 cial fertilizers. He gave careful explanation of all ana- 

 l\i;ical processes, the reasons for them and the results 

 obtained ; then, following the method of Adolph Stoeck- 

 hardt, he ''valued" the fertilizer analyzed as an 

 assayer values an ore, by assigning a money value to 

 each essential ingredient, and from their proportion, 

 as found in the sample, deducing a market value for 

 the fertilizer. 



which was soon adopted by the chemists of the agricultural societies of 

 Great Britain. 



