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386 Chronicles of Science. [July, 
management during the growing and the feeding periods, which 
are now understood to be coincident from beginning to the end of 
each, was fully discussed by Mr. Robert Smith before the London 
Farmers’ Club, and by Messrs. Hope, Wilson, and McCombie, before 
the Edinburgh Chamber of Agriculture. The special details of 
cultivation and field management necessary to a large production 
of food for live stock on the farm have been carefully described by 
Professor Wrightson, of the Royal Agricultural College, before the 
Cirencester Farmers’ Club, and by Mr. Alderman Mechi, before the 
Wenlock Farmers’ Club: and capital papers on the general 
management of live stock, and on that particular treatment of this 
department of farm management which the cattle plague has called 
forth, have been delivered before English, Scottish, and Insh 
Farmers’ Clubs. The society which has probably done least for 
any serviceable mitigation of the calamity which has befallen us 
is the Royal Agricultural Society of England, whose council were, 
at the late general meeting of the society, taken vigorously to task 
by Mr. Arkell, a Wiltshire farmer, for the inaction they had dis- 
layed. 
: ie must except from the charge of that usually deficient and 
imperfect discussion of agricultural subjects which they receive at 
the occasional meetings of the English Agricultural Society, one 
very instructive lecture recently delivered in its rooms by Dr. 
Voelcker, on the proper conditions of field-experiments. The 
followimg were the points to which he referred :— 
1. Such experiments need not be on a large scale. One- 
twentieth part of an acre of root crop, one quarter of an acre of 
corn or grass, will answer fairly any simple question that is put to 
it by the application of a manure. A larger extent sometimes 
involves a fatal difference of treatment in the several parts of it, and 
unless the plots be small enough to be treated virtually together, the 
results will not be capable of comparison. 
2. These experiments ought to be conducted on soil of what 
may be called an indifferent character —level, fairly drained, 
uniform as to depth, and without any marked character as to com- 
position or texture. It should be neither stiff nor light; nor should 
it be too rich, for as the distinctive effect of different foods cannot 
appear in the case of a man already fully fed, so manures cannot 
produce their characteristic effect, or indeed any effect at all, on soil 
already full of all that plants require. 
3. The result of the experiment depends on the time and mode 
in which it is conducted. As to time:—Experimental manurings 
on grass lands on which it is proposed to try the effect of slowly 
dissolving fertilizers should be done in autumn. Even ammoniacal 
salts may be applied in autumn, if on land possessing any retentive 
character. Nitrates, on the other hand, which the soil allows to 
