PROFESSIONAL BIAS TO BE GUARDED AGAINST. 43 



vour of his own theoretical views. For a similar reason, they 

 listen with suspicion to details of experimental results obtained 

 by persons whose character or profession is in any way sug- 

 gestive of doubt, or of a want of familiarity with practical 

 operations. Thus, the fact that Mr Lawes is himself a manu- 

 facturer of chemical manures, has led some unjustly, I believe 

 to detract from the value or trustworthiness of the field experi- 

 ments and analytical researches made upon his farm in Hert- 

 fordshire. And, in like manner, in the neighbourhood of Lille, 

 where Kuhlmann is also a manufacturer of manures, the ex- 

 periments made under the direction, and published by this 

 gentleman, have, as I gathered upon the spot, been followed by 

 little practical benefit. The knowledge possessed by these 

 practical chemists, and their familiarity with the subject, in 

 reality make them more qualified than others both to suggest 

 and to superintend experiments in the field, whether compara- 

 tive or absolute. The results they publish, therefore, ought to 

 be received and confided in at least as implicitly as those of 

 other parties. 



Still, it is much to be wished, not only that field and other 

 experiments in husbandry should be extensively undertaken, 

 and that they should be skilfully and conscientiously performed ; 

 but that persons should be employed upon them, to whose 

 results no breath of interested suspicion could by any one be 

 imagined to attach. 



4. Quantity of land required for a continuous series of field 



experiments. 



This inquiry may be considered of interest, in reference either 

 to the performance of experiments, year by year, upon an 

 ordinary farm of some extent, or to the establishment of what 

 may be called an experimental farm or garden, in which ex- 

 perimental culture only is to be carried on. 



In regard to the former, it is sufficient to observe that there 

 appears no necessity for having a special portion of land set 

 apart for experiments, since, year by year as the crops are 

 changed, a convenient part may be chosen, which, because of 



