78 IS IT DESIRABLE THAT PRACTICAL 



different persons and in different places, are not to be rejected. 

 We are not to set a good result against a bad one, and to allow 

 them, in our minds, to neutralise each other, and thus reject 

 them both. We ought rather, if the experiments have been 

 made with equal care, to receive both as expressions of the 

 truth under the circumstances in which each has been obtained. 

 Where the differences are remarkable, we ought to inquire 

 what the special circumstances have been from which differences 

 so large can have arisen. 



In this branch of experimental inquiry, we cannot, as I have 

 said, set a positive against a negative result, or vice versa. In 

 the positive, so much truth may be actually and visibly gained ; 

 but in the negative, we may have a no less valuable indication 

 of the existence of circumstances by which the ordinary effect 

 of a given substance may be wholly prevented. The search 

 after these circumstances may lead us to truths no less impor- 

 tant than those which may appear to flow from the positive 

 result ; and thus, in the words of Bacon, " though what suc- 

 ceeds may please more, what succeeds not may inform no less." 



I need not add, what every practical man will say to himself, 

 that any experimental result which is inconsistent with general 

 experience must be very cautiously received, and submitted to 

 searching criticism and careful repetition. 



9. Is it desirable that experiments in practical and scientific 

 agriculture should be extensively made f 



This question may be considered in several aspects. 



1. Is it desirable for the state ? Everything which is likely 

 to increase the gross agricultural produce of a country, if not 

 too costly, must be desirable for the state. The permanent 

 wealth and power of a great country depend upon the produce 

 of its soil, and the one must increase with the other. 



" It may with certainty be stated," says Lampadius, " that 

 by the use of gypsum, the produce of clover, and the conse- 

 quent amount of live stock, have been increased in Germany 

 at least one-third."* This illustration is sufficient to prove the 

 importance of agricultural experiment to the national welfare. 

 * Die lehre ton den Mineralischen Dungmitteln, p. 34. 



