the Progress of English Agriculture. 835 = 569 
enty plots, from one-quarter to one-half an acre each, were 
arked out, of which two have been left continuously without 
anure, and each of the others has received its own special 
anure, and, as a rule, the same description year after year. 
Some plots were manured exclusively with salts of ammonia 
. nitrate of soda ; others with purely mineral manures of various 
nds, some being of a more mixed character, including phos- 
ates and salts of potash ; others being composed chiefly of 
osphates without potash. Again, on other plots, the effect of Effects ou the 
J xed minerals and nitrogenous and animal manures in various herbage. 
japortions on the mixed herbage was tried. 
Under this varied treatment, a remarkable change in the flora 
Icame apparent, even in the first years of the experiments, and 
i later ^ ears these changes have been more fully developed ; 
s much so that the herbage of most of the variously manured 
])ts now presents a striking contrast to that of the unmanured 
j>ts. 
On the plots manured with large quantities of ammonia, the 
fer grasses, as well as the clovers and other leguminous plants, 
i a few years disappeared all but completely, as if by magic ; 
a l on the other hand, on those plots to which potash and 
s )erphosphate were applied clovers and other Leguminosae 
E de their appearance in increased numbers and vigour. 
Dr. Gilbert summarises the general results of the experiments Results of the 
befly as follows : — experiments. 
The mean produce of hay per acre per annum has ranged on 
t. different plots from 23 cwt. without manure to about 64 cwt. 
0 the plot the most heavily manured. 
The number of species found has generally been about 50 on 
tl unmanured plots, and has been less on the most poorly 
nnured plots. 
species belonging to the order Graminea? have, on the average, 
* tributed about 68 per cent, of the weight of the mixed 
h bage grown without manure ; about 65 per cent, of that grown 
b purely mineral manures (that is, without nitrogen) ; and 
a >ut 94 per cent, of that grown by the same mineral manures, 
wh a large quantity of ammonia-salts in addition. 
•pecies of the order Leguminosae have, on the average, con- 
;i)uted about 9 per cent, of the produce without manure, about 
1 per cent, of that by purely mineral manures (containing 
pash), and less than 0-01 per cent, of that by the mixture of 
tl same mineral manures and a large quantity of ammoniacal 
s; s. 
'pecies belonging to various other orders have, on the average, 
C(tributed about 23 per cent, of the produce grown without 
• aure, about 15 per cent, of that grown by purely mineral 
