153 THE PRINCIPLES OF 



credited, well-established fertilizers. It is not anything 

 against a fertilizer at all, but in conducting agricultural 

 experiments we must always be guided by contrast or by 

 comparison, and if our land is in such condition that our 

 unmanured plot gives a high result, of course our manured 

 plots give a less showy or a less marked result than if 

 we have a miserable failure on our unmanured plot. On 

 bad land, or land that is out of condition, our unmanured 

 plots yield very little, the ground being in a state of deple- 

 tion, and where we have applied the fertilizer, there we 

 see a great effect. M. Ville, when making experiments on 

 the values of artificial fertilizers, did well to select the very 

 poorest soils that he could possibly get hold of, and soil that 

 gives a minimum result on an unmanured plot is sure to 

 respond well to fertilizers and to give a good comparative 

 result. This is an important fact to be remembered by 

 agriculturists, simply because the farmer who has his land in 

 high condition would do well to pause before he purchases 

 fertilizers. They pay best where we enter upon a thoroughly 

 worn out farm, but if we enter on land in high condition it 

 is a question whether we will not throw our money away 

 upon bought manures. 



There is another aspect of this question which I wish to 

 open up, and that is the climate. A moist, cool climate 

 is the climate for exhibiting the effect of these artificial 

 substances, and as we travel southwards and approach those 

 regions where a hot and droughty summer may be expected, 

 artificial manure ceases to be of constant value. Thus, 

 in the south of Europe, I understand that it is only once 

 in several years that artificial manure produces an effect, 

 but dung continues to produce an effect. In the hotter 

 portions of Europe we shall find that dung, especially dung 

 produced with artificial food, such as oil-cakes, holds its place, 

 and can be relied upon, while lime, nitrates, nitrate of soda, 



