86 
REPORT ON THE INDUSTRY OF MANURES. 
It was in the year 1837 that the British Association for the Advancement of Science, 
perceiving the immense accumulation of facts, for the most part unsystematized, which 
had already taken place in organic chemistry, and was annually increasing therein, in¬ 
vited Justus Liebig, who had already attained to eminence by his extensive researches in 
this branch of science, to write a report upon its then condition ; which honourable duty 
the illustrious philosopher undertook. 
In the year 1840, Liebig, in fulfilment of this engagement, produced his memorable 
work on ‘ Organic Chemistry in its Applications to Agriculture and Physiology.’ 
In ordinary hands, such a report would, in all probability, have been but a compilation, 
more or less compendious, of facts already known, and conceptions already proposed for 
their co-ordination. But the original genius of Liebig, essentially philosophical and 
constructive, impressed upon his work a very different character. 
He began by sweeping away the fallacious theoretical views which were at that time 
in vogue—particularly the so-called “ Humus theory,”—and replacing them by a theory 
of his own, wider in scope, and more conformable with truth. With this, the so-called 
“ Mineral theory,” as a general clue for his guidance, Liebig was enabled to thread the 
labyrinth of intermingled facts and fallacies, which had necessarily resulted from so 
many investigations, inductive and deductive, carried on for so many years, by so many 
independent thinkers and experimentalists, and recorded in so many scattered memoirs. 
All these he was enabled to weigh and appreciate, by the criterion of a new law, or 
rather system of laws, themselves evolved during his large induction, and established (in 
a great measure) by help of the very facts they served to elucidate and connect. 
Profiting by the controversial criticism which his book, on its appearance, did not fail 
to provoke, Liebig made it more perfect in successive editions; and extended it by ad¬ 
ditional volumes, some modestly entitled ‘ Familiar Letters,’ some promulgated as codes 
of Natural Law, but all forming parts of a connected series, in which, as in a mirror, is 
displayed the progressive development of Liebig’s views, in the light of his own and of 
contemporary researches. By these labours, pursued with unwearied industry during 
upwards of twenty years, Justus Liebig has unquestionably shed upon his all-important 
theme a flood of light, as copious and brilliant to the full as that which it successively 
received, in former days, from the luminous minds of Lavoisier and Davy. 
Indeed, of the affiliation of his labours to those of his immediate predecessor, Liebig 
himself, in the dedication of his work to the British Association, speaks with becoming 
humility, and justifiable pride:— 
“ I have endeavoured,” he says, “ to follow the path marked out by Sir Humphry 
Davy, who based his conclusions only on that which was capable of examination and 
proof. This is the path of true philosophical inquiry, which promises to lead us to 
truth—the proper object of our research.” 
Of Liebig’s views, and of the rapid and profound revolution of opinion they brought 
about, occasion will arise to speak in a subsequent page. Meanwhile, it may suffice to 
remark that, amongst other things, they completely overthrew the conceptions pre¬ 
viously entertained as to the nature and operation of manures. 
Modern History of Manures .—The impulse given by Liebig’s first book to manurial 
industry is very distinctly traceable in the registry of British patents. 
During the ten years which followed its publication, i. e. between 1840 and 1850, no 
less than thirty-six patents for manurial processes and products were enrolled ; being six 
times as many, in ten years, as had been obtained in ail preceding time since patents 
were first granted. 
During the next five years this manurial movement went on in an accelerating ratio ; 
no less than ninety-six more patents having been registered between 1850 and 1855. The 
lowering of the charge for patents, which occurred during this interval, no doubt had its 
share of influence on this result. 
The patent statistics since 1855 are not before the Reporter; but he is enabled to 
state, in general terms, that the activity of research and invention in this department 
has by no means declined during the last seven years, and that the manurial inventions 
brought forward in England since 1840 may be apprcximatively estimated as numbering 
at least 200. 
This long series of inventions comprises plans and processes for turning to account, as 
manure, almost all the known forms of animal waste and ejecta ; such as, for example, 
the night-soil and sewage of towns ; the rags of woollen, silken, and leathern clothing ; 
