4 Experiments with different Top-dressings upon Wheat. 



ganic matter can be given, is altogether wanting. It is true the 

 experience of practical men affords certain useful indications to 

 the scientific observer, but nothing more. In the absence of 

 clear, unmistakeable, and sufficiently extensive practical evidence, 

 no definite answer can be given to the question so frequently 

 addressed to the agricultural chemist, Shall I apply nitrate of 

 soda or guano upon my wheat ? 



We do not know, even in a general way, the comparative 

 efficacy of nitrates and of ammoniacal manures : how is it 

 possible, I would ask, to answer such a question in a particular 

 instance ? The importance of this question will be admitted by 

 every one, especially at a time when the price of corn is low, and 

 that of Peruvian guano high. Extensive deposits of nitrates of 

 potash and soda are more likely to be discovered when diligent 

 search is made after them than new and extensive deposits of 

 guano equal to, or approaching in efficacy, Peruvian. Apart 

 from the theoretical aspect,. the question as to the relative merits 

 of nitrogen in the shape of nitric acid or ammonia is of great 

 practical interest. Fully impressed with the importance of 

 this subject, I have undertaken, at the request of the Council of 

 the Royal Agricultural Society, a series of field experiments 

 with top-dressings upon wheat, and have now the pleasure of 

 laying before the members of the Society the results of a series 

 of experiments made last season (1859). Similar experiments I 

 hope to continue from year to year ; for the longer I am engaged 

 in carrying out experimental trials in the field, the more I am 

 convinced that the experience derived from one, two, or three 

 years' experimenting in the field is alike inadequate to further 

 the progress of scientific agriculture, and to supply the farmer 

 with information from which he can derive practical advantage. 



The time has arrived when an extension of field experiments 

 is imperatively demanded. Practical experiments should be 

 instituted in all parts of the country, and tried on every descrip- 

 tion of soil, and under the most varied conditions. They should 

 be conceived in a philosophical spirit, and carried out with that 

 accuracy and love of truth which ought, and generally does, cha- 

 racterize the labours of the student of natural science. Mere 

 random trials, made without plan or definite object in view, are 

 only calculated to lead astray, and thus do more harm than good. 

 Unfortunately, success in a field experiment cannot be always 

 secured : the disturbing influences which spoil the result are 

 numerous and frequently uncontrollable ; and, as the labour, 

 anxiety, and expense which attend field experiments are very 

 great, it can hardly be expected that many agriculturists will 

 engage in this work. After having gone to the trouble of pre- 

 paring and measuring out the land, selecting the seed, procuring 

 and weighing out the various fertilizers intended for trial, after 

 having them analysed and taken notes from day to day of the 



