OF AGRICULTURE. 35 



half acre for the purposes of experiments ; feeling, as 

 he said in a lecture on the subject, that the objects 

 of the foundation of the Professorship of Rural 

 Economy — * would not be fully attained until the 

 holder of it was enabled, not only to retail the in- 

 formation he might obtain from books, but also to 

 illustrate it by experiment, and to verify, as well 

 as extend the knowledge he might have derived from 

 others through original investigations of his own.' 



Briefly described, the subjects which Dr. Daubeny 

 indicated as suitable for such enquiry were — i. To 

 determine what amount of mechanical treatment, and 

 what length of time, would be required to bring an 

 exhausted soil back to fertility without manure. 

 2. To try whether, if a soil be rich in mineral con- 

 stituents, ammoniacal manures may not be dispensed 

 with by the use of mechanical operations; since, as 

 he says, Liebig's. opinion is, that many plants have 

 the power ' of absorbing from the atmosphere so 

 large an amount of ammonia, as would seem to 

 render them independent of animal manures, and to 

 enable them to derive all their ingredients, except 

 their mineral ones, from the atmosphere.' 3. The 

 causes of the failure of clover. 4. The effects of 

 gypsum applied as manure. 5. To try whether there 

 is any disadvantage in the use of superphosphates 

 from which the fluorine has been dissipated, com- 

 pared with bones from which it has not. 6. Whether 

 growing plants year after year on the same land 

 from the seed yielded, tends to variation, or to the 

 obliteration of specific characters. 7. Lastly, to de- 

 termine how far the growth of the fungi which 

 attack different crops may be considered as a cause, 

 or only the effect, of disease. 



I may here say that much experimental evidence 



D 1 



