Steam Cultivation. 
321 
modern agricultural literature probably consists of the recorded 
experience of practical men — men who, at a risk of loss to them- 
selves, have diverged from the beaten track, acting as pioneers 
for their neighbours, and, whether successful or otherwise, have 
dared to give in faithful detail the various results of their experi- 
mental practice. 
Practical Details. 
In order to arrive at an approximate estimate of the value of 
an act of cultivation, it is essential to have a general idea of the 
physical constitution of the soil operated on. This will furnish 
a key to many difficulties— a touchstone that will reconcile many 
apparent anomalies and contrarieties. Clay, loam, sand, are only 
relative terms ; a soil, for instance, that cultivators of one district 
might term loam, would differ materially from that which would 
be so classed in another district. Hence to take the acreage got 
over as a test of the economy of cultivation, irrespective of the 
nature of the soil, may be delusive, since this is no definite 
measure of the amount of resistance overcome. In estimating in 
different districts the respective value of steam or any other mode 
of cultivation, these premises should be borne in mind. 
The soil on which our experience has been gained is derived 
from, and in its composition partakes largely of, the Oxford clay. 
The subsoil — the clay proper — is extremely stiff, close, and im- 
pervious, and is covered by the surface-soil to a depth varying 
from 4 to 7 inches. On this geological formation, where the 
parent clay predominates in the composition of the surface, the 
soil formed is invariably very retentive and tenacious, and there- 
fore difficult and expensive to cultivate. Its natural characteristics 
have been aptly described by the remark " that in winter, such 
soils are like glue, and in summer, cast-iron." 
We had hoped to have given the dynamometrical measure of 
the draught for a common plough at a given depth, but circum- 
stances prevented this. To practical men, however, the number 
of horses usually requiied in a plough will convey a fair idea of 
the nature of a soil ; and when we mention that on the class of 
soils to which our remarks refer, three, four, five, and occasionally 
six horses, may be seen in a plough, it will readily be inferred 
that they may properly be classed as strongest among the strong. 
In our practice three horses are required for common seed- 
furrow ploughing ; while for deep work (9 and 10 inches) it is 
found extremely hard work for four horses to get over three- 
quarters of an acre per day. 
These horses, be it observed, are not specimens of the poor, 
badly-fed animals which are so frequently seen as a characteristic 
feature on the small farms in clay districts, but well fed and 
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