314 
The late Dr. Voelcher. 
modify the conclusions at first drawn as to the degree in which 
ammonia was absorbed. 
As the result of the whole enquiry, he called attention to the 
fact that the most important soluble constituents of manures are 
rendered less soluble, but not quite insoluble, when applied to 
the soil. 
As already intimated, he instituted numerous field experi- 
ments with different manures, on different crops, on the College 
farm, and in the conduct of these he was very materially aided 
by his friend and colleague, Professor Coleman, now of York. 
He also, not long before he left Cirencester in 1863, en- 
deavoured to enlist the co-operation of intelligent practical 
farmers in different localities in the conduct of field experi- 
ments, and as time went on he carried out the plan more and 
more systematically. In most, if not all, cases of such field 
experiments, he made a complete analysis of the soil upon 
which the experiment was to be conducted. 
In his reports of field experiments he conscientiously recorded 
failures as well as successes, and he was very careful not to 
draw general conclusions from results obtained on land of one 
description in a given condition from previous treatment, or in 
one season only. Thus, we find him saying, in reference to 
one such result : " In dry and unfavourable seasons, the very 
best manures are much more likely to do harm than poor or 
indifferent fertilisers." Again : " In a bad and very dry season, 
it is well known that concentrated artificial manures often do 
harm to crops, whereas no injury to them results from the 
application of indifferent and all but valueless compounds sold 
as artificial manures." And again : " Agricultural experiments 
are of little or no practical utility unless they are continued 
from year to year for a long period, and tried on a variety of 
soils in good and bad seasons in a manner which allows us, it 
not to eliminate, yet clearly to recognise, the disturbing in- 
fluences of climate, season, condition of soils, and other cir- 
cumstances, which often affect the produce in a higher degree 
than the manures on which we experiment. A single field 
experiment is as likely to lead us in a wrong as in a right 
direction." 
Still, much useful information as to the actual and compara- 
tive value of the different artificial manures in the market, and 
of their aptitude to different soils and to different crops, was 
brought out by the results of the very numerous field experi- 
ments that were so made under his direction. 
Nevertheless, he hailed with much satisfaction the inaugura- 
tion of the more systematic series of field experiments now in 
progress at VVoburn, conducted there on behalf of the Royal 
