TRANSACTIONS OF THE SECTIONS. 81 
of this so-called aluminium bronze give it great value, and it seems likely to find 
much favour for its appearance. Mr. Bell has also rendered no small service to 
science by collecting a large quantity of that wonderful new metal, thallium, and 
preparing several new salts. Among alloys, a variety of brass containing a small 
quantity of iron has recently attracted considerable attention. The alloy is by no 
means new, though hitherto known but to few persons. It combines tenacity with 
elasticity to a remarkable degree, and can be easily forged. 
Most of the members of the Section are probably aware of the admirable series 
of agricultural experiments which have been proceeding for the last twenty years, 
under the direction of Mr. Lawes, of Rothamsted ; yet many are probably unaware 
of the vast importance of the results already established by those experiments. Few 
things are perhaps more difficult than to conduct scientific experiments in any 
practical art like farming; to find how the resources which science discovers can be 
profitably turned to account, or how the defects which theory points out, in ordinary 
working processes, can be profitably remedied. It is almostproverbialthat the greater 
number of persons who attempt the introduction on their farms of plans suggested 
by abstract science, succeed only in finding how to lose money. It does indeed require 
a rare combination of enthusiasm with caution, of knowledge of theory with 
practical experience of the conditions of ordinary working, to carry such experi- 
ments to a definite and useful issue. Such rare combinations of qualities have 
existed in Mr. Lawes; and when we recollect that by associating Dr. Gilbert with 
his labours he obtained the cooperation of an able and accomplished chemist, we 
have no longer reason to wonder that the results of twenty years’ continuous ex- 
periment, conducted on an ample scale, with the most-scrupulous care and systematic 
order, should have led to the establishment of results so numerous and important 
pn secure for Mr. Lawes the highest rank among the founders of scientific agri- 
culture. 
In speaking of the chemistry of agriculture, I cannot omit alluding to the writings 
of Licbig, which have rendered such important services by bringing vividly before 
the English agriculturists what was known of the chemistry of farming, and several 
ingenious and suggestive theories relating to practical agriculture. In the intro- 
duction to the last German edition of his ‘ Agricultural Chemistry,’ Liebig refers 
in terms of studied disrespect to the investigations of Mr. Lawes, and while mis- 
quoting a paragraph in one of Mr. Lawes’s publications, endeavours to convey the 
impression that that gentleman was unacquainted with the correct use of the term 
“ mineral,” and had misunderstood Liebig’s mineral theory; which he is generally 
considered to have disproved. I mention this circumstance with pain, and have 
no doubt that all who value Liebig’s truly important scientific labours will regret 
it as much as I do, 
Another practical question which science has latterly brought prominently before 
the attention of the public is that of the utilization of the drainage of towns. It 
is estimated that the quantity of nourishment for plants wasted in London alone in 
this form is worth about a million sterling per annum; but this valuable material is 
contained in so large a quantity of water, that no plan has come into working for 
separating it out profitably for use. Some persons are of opinion that the sewage 
might with advantage be conveyed through pipes for use in the fields, especially on 
meadow land, to which it is most easily applicable. Baron Liebig has written a 
letter on the subject, which was forwarded by Alderman Mechi to the ‘ Journal of 
the Society of Arts,’ containing a proposal to mix the liquid with superphosphate 
of lime before distributing it, by which he considers that the value of the con- 
stituents already contained in the liquid will be practically increased. It is, how- 
ever, not likely that the opinion of a chemist will decide the authorities to adopt 
an experimental scheme of the kind, as it is really rather an engineering and com- 
mercial than a chemical question. The practical test of value commercially, is how 
much an article will fetch, and the data of this kind before us do not lead to the 
anticipation of a profit at all approaching to what theory suggests from the sale of 
this refuse. At Croydon (a town of about 18,000 inhabitants) it appears that the 
use of the whole sewage has only added about a thousand pounds to the rent of a 
farm on which it is used. 
Another refuse material which has already come to possess great value is coal- 
