508 Report of Experiments icith different 3Ianures 
influence of the different manures ; and those given further on 
relating to the chemical composition of the hay, and to the 
amount of constituents removed from the land, will lead to the 
conclusion that some of the manures have so forced the crop as 
materially to reduce the available store within the soil of some 
constituents which the manures themselves did not supplv. On 
the other hand, even with 14 tons of farmyard manure per acre 
per annum, doubtless supplying annually much more of every 
mineral constituent than would be removed in the crop, the rate 
of increase is very little higher during the last four than during 
the whole seven years of the experiments. 
With ammonia-salts alone (Plot 4) there has been an average 
increase over the seven years of about 8 cwts., and with ammonia 
salts and sawdust (Plot 5) of about 9 cwts. of hay per acre per 
armum ; but over the last four years, of only about 5| cwts. with 
ammonia salts alone, and about 7J cwts. with the sawdust in 
addition. It is obvious, therefore, that, when ammonia salts 
were used year after year without mineral manure, there was an 
undue exhaustion of the mineral constituents of the soil. That 
this was so is confirmed, not only by the fact of the deteriorated 
character of the herbage, as shown by the results of the botanical 
examinations recorded in the last IN umber of the Journal, but 
also by the evidence relating to the chemical composition of the 
produce, • 
alone ' have no effect ; that, in order to be efiBcacious, they must be accompanied 
by the mineral constituents, and that the efifect is then proportional to the supply 
— Eot oi ammonia, but of the mineral substances." — Friuciples, p. 55 (1855). 
" These two paragraphs are altogether irreconcilable ; for if Mr. Lawes admit 
that the miiteral constituents are indispensable to plants, how can he maintain that 
these very mineral constituents are replaceable by ammonia, that is to say, that by 
means of ammonia we altogether dispense with them ? " — Principles, p. 89 
(1855). 
" It has been mentioned in the preceding part of the chapter, that animal excre- 
ments may be replaced in agriculture, by other materials containing their consti- 
tuents. Now, as the principal action of the former depends upon their amount of 
mineral food so necessary for the growth of cultivated plants, it follows, tliat we 
might manure with the mineral food of wild plants, or, in other words, with 
THEIR ASHES [the Capitals are Baron Liebig"s own] ; for, these plants are governed 
by the same laws, in their nutrition and growth, as cultivated plants themselves." 
-^3rd Edition, p. 183 (1813). 
" But the weight or amount of the crops is in proportion to the quantity of food 
of both kinds, atmospheric and mineral, which is present in the soil, or conveyed to 
it in the same time. By manuring with ammoniacal salts a soil rich in available 
mineral constituents, the crops are augmented in the same way as they would have 
been if we had increased the proportion of ammonia in the air." — Principles, 
p. 77-8 (1855). 
These sentences will be sufficient to show whether or not Liebig is justified in 
now attempting to fall back, in agricultural discussions, upon the more strictly 
scientific meaning of the terms " mineral " and " inorganic," so as to include 
within them " ammonia," " ammoniacal salts," " atmospheric constituents," &c., 
and thus to give a new definition to his mineral theoi^, or rather substitute at this 
date for his own theory, which has proved to be erroneous, another not his own. 
