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MESSRS. J. B. LAWES AND J. H. GILBERT OR THE RESULTS OF 
amount of potass in the crops grown. Further, on the examination of the soils of some 
of the plots of that same field, Baron Liebig’s son, Hermann von Liebig, found the 
amounts of both potass and phosphoric acid considerably greater, especially in the 
upper layers, the greater had been the previous supplies by manure. Lastly, Dr. 
Voelcker’s analyses of the drainage waters from the different plots of the same field 
showed very much less loss of potass in that way than of either soda, lime, or magnesia, 
and also very much less of phosphoric acid than of sulphuric acid or of chlorine. There 
was in fact comparatively little loss by drainage of either potass or phosphoric acid. 
To sum up in regard to the effects of the different mineral manures when used 
without artificial nitrogenous supply : the comparison of the results obtained without 
manure, with superphosphate of lime alone, and with a mixed mineral manure with, 
and without, potass, brings clearly to view the much more striking influence of an 
increased supply of potass, than of lime, magnesia, soda, phosphoric acid, or sulphuric 
acid ; and it will be observed that this is quite consistent with the facts adduced in 
Table I., and context, in regard to the mineral composition of the hay crop. It is true 
that when there was either a direct supply, or an available residue, of potass at 
command, more of the other constituents enumerated above were taken up, and even 
when superphosphate of lime was used alone, considerably more phosphoric acid was 
taken up, but coincidently with this there was but little increase of produce, and very 
little increase in the amount of nitrogen assimilated. 
The more special effects of the mineral manures, and particularly of the artificial 
supply of potass, on the botanical and chemical characters of the herbage, will be 
discussed in Parts II. and III. 
Having now considered the results obtained by nitrogenous manures alone, and by 
mineral manures alone, we have next to call attention to those yielded by mixtures of 
the two. Following somewhat the same order of illustration as in regard to nitrogenous 
manures used alone, we wall discuss-—first the effects of a given amount of nitrogen 
applied as ammonia-salts, then of double the quantity, then of the same (the single) 
amount applied as nitrate of soda, and then of half the quantity, also as nitrate, in each 
case used in conjunction with the same mixed mineral manure, including potass, as that 
applied to plot 7 ; and, following the same order as with the mineral manures used alone, 
comparison will then be made of the results obtained by the ammonia-salts alone, by 
the same with superphosphate of lime, with the mixed mineral manure including potass, 
and with the mixed mineral manure excluding potass. 
7. 400 lbs. Ammonia-Salts with Mixed Mineral Manure containing Potass; Plot 9. 
The next table shows the residts obtained by this mixture, side by side with those, 
over the same periods, by the same quantity of ammonia-salts used alone, and by the 
same mixed mineral manure used alone. 
