Agricultural Chemistry. 
427 
Again, the Council of the Royal Agricultural Society of 
England undertook a series of investigations as to the composi- 
tion of the ashes of agricultural plants, with the object, in ac- 
cordance with the doctrine of Baron Liebig, of ascertaining the 
manures required to restore to land its productive capability lost 
by the removal of previous crops, or to prepare it for the sub- 
sequent gi'owth of this or that agricultural plant. In the course 
of this inquiry their able chemist actually provided recipes on 
the principle alluded to. But, as we well know, his own judg- 
ment and sagacity led him to doubt the sufficiency of the plan 
submitted to him to answer the ends supposed, long before his 
task had been concluded. Nor need we remind the reader, that 
investigations of a similar kind, and instigated by the same sug- 
gestions, have been made in many of the European laboratories 
with the same object ; or further, that an immense number of 
manure-making schemes have arisen in England, Germany, 
France, and America, professedly founded on the principle 
alluded to. 
In the ' North British Agriculturist ' of November 7, 1855, 
the editor thus defines Baron Liebig's views : — 
" Now, according to Liebig, ammonia is always afforded by the atmosphere 
in excess, while mineral matters, if not always, are at all events generally 
deficient in the soil ; hence his inference is, that in order to increase the crop, it 
is only necessary to add the latter. He does not assert that ammonia is use- 
less : on the contrary, he would have every farmer to add it to his soil, and 
that abundantly, if he happens to possess it ; but if he proposed to lay out a 
certain sum of money in the purchase of manures, he would coimsel liim to 
expend it on mineral matters, and trust to the atmosphere for the ammonia, 
which he belie^'es may be obtained from it in quantity more than siifficient for 
the lanjest crop which it is possible to ohtain." 
Professor Johnston, in a lecture delivered at the York 
Meeting of the Royal Agricultural Society, in 1848, says : — 
" A third opinion adopted by many, and extensively acted upon by some, 
is, that plants obtain all their organic matter directly from the air, and derive, 
and therefore reciuire, only mineral matter frora the soil.* " — Jour. Hoy. Ayr. 
Soc. Eng., vol. ix. part 1, p. 223. 
And, in a note to which attention is drawn by the star given at 
the end of his sentence. Professor Johnston gives the very sen- 
tence from Baron Liebig, which we are ourselves so much com- 
plained of for quoting, thus : — 
" * ' The crops on a field diminish or increase in exact proportion to the dimi- 
nution or increase of the mineral substances conveyed to it in manure. — 
Liehiy.' " 
In France — M. Boussingault, whose competency to judge of 
such matters is second to none in that country, and whose high 
character and authority as a philosopher and an agricultural 
chemist no one will doubt, thus indicates both his understanding 
and his opinion of Baron Liebig's doctrine — 
