236 £ECTIONAL ADDRESSES. 
generally useful. Further, he showed that mineral calctum phosphate 
gave the same product, and so could be converted into a valuable manure. 
All this was done before Liebig’s report of 1840 appeared ; the work was 
so novel that Lawes was able to take out a patent for it and so to found 
the artificial fertiliser industry. He did not at once do this, being 
dissuaded by his friends—in 1838 a gentleman and a landowner did not 
embark in trade, least of all in the manure trade—he waited till 1842. 
He set up a factory at Deptford Creek, though I am unable to find the 
source from whence he obtained his phosphates in the early years, nor 
indeed can I recover much information about those years; fortunately 
there is some record, for in 1851 he took proceedings against various 
persons for infringing his patents, and the papers preserved at Rothamsted 
tell us much about the history of the discovery. 
Simultaneously with all this, however, the field experiments at 
Rothamsted were developed, and of these the records are very full. They 
arose out of the pot experiments, but were quickly expanded to controvert 
Liebig. Lawes recognised that he could not look after both these and the 
factory, and in June 1843 he brought in Gilbert to have charge of them, 
giving him as laboratory the barn in which the chemical work had hitherto 
been done. Lawes, and especially Gilbert, had all the Victorians’ love of 
controversy. They did not attempt to rehabilitate the old humus theory, 
nor did they dispute the necessity for potash and phosphates ; they showed, 
however, that these so-called mineral manures were not sufficient, nitrogen 
must also be given ; Liebig had denied this. . Secondly, they showed that 
the composition of the plant afforded no guidance as to its manurial 
requirements. Turnips contained but little phosphate and much potash, 
yet they responded to phosphatic far more than to potassic fertiliser. 
Lawes and Gilbert remained faithful all their days to their first love, 
nitrogen; and both at Rothamsted and many years later at Woburn, the 
whole scheme of field experiments revolved round this need for supplying 
nitrogenous fertiliser. The fame of Rothamsted, however, grew up on 
the three field experiments; on» Broadbalk wheat, the most important 
crop of the time, showing on the untreated land the 20 bushels per acre 
familiar to the farmers of the 40’s, and on the plots treated with the new 
artificial fertilisers, especially with sulphate of ammonia, the unusually 
large yields of 35, 40 or even 50 bushels; the Barnfield, where Lawes’ 
superphosphate gave remarkable increases in yield of turnips, the next 
most important crop; the increases were at least as good as could be 
obtained with the best farmyard manure, which then, as now, was scarce ; 
and the adjoining Agdell field showed the great value in the rotation of 
clover, a fact which was not new, but sufficiently little known to make 
the demonstration very interesting. Never before had an experimental 
farm such a striking display of new discoveries ; never before had it been 
possible to show how this wonderful science about which people were 
talking so much, could do so much for agriculture. The Rothamsted 
fields were the first effective demonstration grounds, and so well did the 
farmers of the day appreciate Lawes’ work that they not only bought his 
superphosphate, but after only ten years, in 1853, they subscribed £1,160 
to build a laboratory which should take the place of the old barn that had 
been in use for some fifteen years. This laboratory was the first of its 
