308 Agricultural Chemistry. 



required for their development will be furnished by the atmosphere." — 

 p. 213.* 



Keeping in mind what I have said in the chapter on manure 

 (pp. 188, 189, 190, 191, 192), concerning the action of the am- 

 monia therein contained, no reader of sound judgment could, I 

 should have supposed, have misunderstood my meaning. 



The reader knows what Mr. Lawes has made of these simple 

 and intelligible propositions. In his conclusion (Journal, vol. 

 xii. p. 39), leaving out the word manure, he misrepresents 

 me as having said, that 



" We cannot increase the fertility of our fields by a supply of nitrogenous 

 products or by salts of ammonia alone, but rather that their produce increases 

 or diminishes in a direct ratio with the supply of mineral elements capable of 

 assimilation." 



In his paper ('On some Points,' vol. xvi. p. 464) he omits 

 the first part of the sentence above quoted, and imputes to me 

 the following general proposition : — 



" Thus, speaking of the supply of ammonia, he (Liebig) says that it may 

 be even superfluous, if only the soil contain a sufficient supply of the mineral 

 food of plants, when the ammonia supplied by their development will be 

 supplied by the atmosphere." 



In the first part of the sentence, to which the Avord " super- 

 fluous " refers, I had specified " most of our cultivated crops." 



By these means Mr. Lawes endeavours to make the world 

 believe that I have taught : — 



1. That the effect of manure is proportional to the mineral 



constituents which it contains alone. 



2. That it is superfluous to supply ammonia in the manure 



to any cultivated plant whatever. -j- 



* The translation here is perhaps not verbally quite exact. Instead of " arti- 

 ficial ammonia" the original has " artificial application of ammonia ;" and instead 

 of " unnecessary for most of our cultivated plants, and that it may be even super- 

 tluous," the German has " dass die Zufiihr fiir die meisten Culturpflanze 

 iinnothig und iiberfliissig sey," which in English means " that the supply (of it) is' 

 unnecessary and superfluous for most of our cultivated plants." The word 

 " superfluous " here refers more directly to " most of our cultivated plants " than 

 in the printed translation. 



t It would certainly be very unreasonable to make me responsible for the 

 erroneous views which othei'S may have formed of my doctrines. That I have 

 never, at any time, held other opinions, than those which I have defended in the 

 preceding pages and in my ' Principles of Agricultural Chemistry,' is surely 

 demonstrated most convincingly in those publications of mine which appeared 

 simultaneously with the third and fourth editions of my ' Agricultural Chemistry.' 

 In my ' Handbuch der Organischen Chemie,' we find, at p. 1398 (published 1843), 

 the following passage : — 



" From the knowledge of the food required by plants are derived several rules 

 highly important in agriculture : — 



"1. By the addition to the soil of decaying vegetables the growth of plants is 

 accelerated ; the produce of carbon is augmented, inasmuch as we thereby supply 

 a source of carbonic acid. 



" 2. By 



