xxii Obituary Notices of Fellows deceased. 
change, and obtained a nearly pure culture of the nitric organism. At 
the same time he showed that organic carbon is not necessary for the growth 
of these organisms, as he had previously imagined, but that they can obtain 
their carbon from carbonates. These results were published in his fourth 
paper on nitrification (1891), and were communicated to the Chemical Society 
only a few days before Winogradski made a similar communication to the 
French Academy. Winogradski, however, had pushed the matter somewhat 
further, having obtained the organisms in bodily form, and having shown 
how they could be cultivated on solid media, a problem which had baffled 
Warington and other investigators. Warington, therefore, had to share his 
final hard-won success with another. 
The practical results of nitrification in the soil were being investigated 
while the search for the organism was still in progress, and Warington began 
along series of determinations of nitrates in the Rothamsted soil, the first 
results of which were published as a lecture given before the Society of Arts, 
for which he was awarded a silver medal. 
When, in 1889, Lawes resigned his active control to the present Com- 
mittee of Management, it was arranged that Warington should leave in the 
following January. Having, however, in the meantime, reached a very 
interesting stage in his work on the nitrifying organism, he stayed on at 
the laboratory till 1891, and succeeded in bringing the work on hand to a 
successful termination. 
Although Warington’s original work in agricultural chemistry was brought 
to a close on his severance from Rothamsted, much useful work remained 
for him to do. The Committee of Management appointed him American 
lecturer. under the Lawes Trust, and he, consequently, proceeded to the 
United States to perform his functions. The six lectures which he there 
delivered dealt chiefly with the subject of nitrification, illustrated by his 
own ‘work at Rothamsted. ey, were published by the United States 
Department of Agriculture. — 
On his return to England, Sir John Lawes invited him to carry out an 
investigation at his tartaric and citric acid factory at Millwall on the 
contamination of these acids by the lead of the vessels used in their 
preparation. This Warington undertook, and he succeeded in finding 
a method for obviating the evil. He obtained, in addition, an excellent 
method for the accurate volumetric determination of lead in the acid. This 
formed the subject of a communication to the Society of Chemical Industry 
in 1893, the last communication of any investigation made by him. 
In 1894, he was appointed one of the examiners in Agriculture under the 
Science and Art Department, and in the summer of the same year he was 
elected Sibthorpian Professor of Rural Economy at Oxford for three years. 
The papers, other than those on original investigations, which Warington 
wrote, are numerous, and are all characterised by a lucidity of expression and 
precision of argument which renders them specially valuable. One of the 
