Artificial Manures for Swedes. 5 



widely from each other in composition, and consequently 

 possessing 1 totally different specific actions on vegetable life, are 

 tried against each other ; or powerful fertilisers occasionally are 

 employed in quantities, or in a mode in which they injure instead 

 of benefiting the plants ; and a variety of other mistakes not 

 seldom are committed, and other circumstances of importance 

 overlooked, which all tend to affect the result of the trial. Thus 

 for instance, experiments with different fertilisers occasionally are 

 tried on land which is in so excellent a condition that the best 

 manure hardly makes any impression on the yield of the crop. 

 It is forgotten that the agricultural capabilities of soils cannot be 

 increased ad libitum to any extent, and that consequently the 

 addition of the most valuable fertiliser to land which has almost 

 reached its maximum state of fertility, which it either possesses 

 naturally, or into which it has been brought by long cultivation, 

 will produce no more effect than the most worthless manuring 

 mixture. Land in such a high state of fertility can be compared 

 to the replenished stomach of a well fattened animal ; the one is 

 as little benefited by the best manure, as the other is by the 

 choicest food. On the contrary, the most powerful fertilisers 

 applied under such conditions are exactly those which may and do 

 occasionally even produce undesirable effects on vegetation, just 

 as the richest food is more apt to spoil a satiated stomach than a 

 plainer dish. 



Hence it is that statements to the effect that such or such a 

 manure has produced as great an effect as the best Peruvian guano, 

 or any other manure of well-known fertilising power, or has even 

 surpassed the best manures in its effects, find their way into the 

 hands of dealers in trashy manures, or to say the best of the 

 manures of a very inferior description. For this .reason the 

 printed testimonials which accompany the offer for sale of 

 artificial manures do not always possess that value which many 

 attach to them, not even when they are the genuine emanations 

 of well-known and strictly honest agriculturists ; for as I have 

 said already, trustworthy inferences from the results of experi- 

 mental trials can only be drawn, if a vast variety of circumstances 

 are taken into account, the recognition of which requires much 

 experience, and I am almost inclined to believe, a special training 

 for this branch of experimental inquiry. Comparatively speaking 

 few men accustomed to practical pursuits during the greater part 

 of their life, and dependent for the support of their families upon 

 their business, are in a position to execute and direct field ex- 

 periments with sufficient accuracy for the results to confer any 

 permanent benefit on the farming community. It is indeed an 

 unjust accusation which is sometimes made against the practical 



