74 
ROYAL HORTICULTURAL SOCIETY. 
manure supplied. Of phosplioric acid, the clovers would re- 
move considerably more than, and of potass about as much as, 
the average of the grasses. Of both constituents the Lotus would 
remove more still, and the Achillea and Flantaqo probably very 
much more. With nitrogenous, but without mineral manure, 
the amounts removed were, as a rule, with all the plants much 
greater than — in fact, in some cases once and a half as much as 
without manure. 
With regard to mineral constituents, therefore, it may be con- 
cluded that the unmanured soils w^ere so far drawn upon by the 
first year's growth, as to widen considerably the difference be- 
tween the unmanured and manured conditions ; and hence the 
series of soils would be better fitted for the purposes of further 
experiment. 
With regard to the nitrogen, although no determinations of it 
in the produce have been made, it may safely be estimated that, 
from the unmanured soils, some of the grasses removed more 
than half as much, the clovers about as much, and the Lotus 
more than twice as much, as was contained in the very heavy 
dressings where nitrogenous manures were employed ; whilst the 
Plantago and the Achillea probably gathered up still more. 
The quantity of nitrogen in the produce was doubtless generally 
increased where it was supplied, but pretty certainly in no case in 
amount equal to the supply. 
In regard to richness in availa.ble nitrogen, therefore, as well 
as mineral matter, the unmanured soils must have been, relatively 
to the others, much reduced, and hence the whole set rendered 
better fitted for further experiment. Calculations and considera- 
tions of the kind here indicated led, in fact, to the decision to 
retain the same soils for the second (the current) year's ex- 
periments. 
If the results of the first season's experiments do not, as 
hardly could be expected that they would, aff'ord very satisfactory 
evidence in regard to the many points of interest which experi- 
ments of the kind are calculated to elucidate, at any rate much 
experience has been gained as to the conduct of future trials ; 
and the discussion of the results themselves cannot fail to indi- 
cate how much we may hope to learn when the unfavourable 
conditions have been avoided, favourable ones carefully secured, and 
the results attentively studied. The relatively varying dependence 
