19 
ration ; so that on this account there is double the 
necessity for draining here. 
Our atmosphere absorbs moisture so rapidly that 
the surface of retentive land is soon baked, and water 
cannot rise from below by capillary attraction, so that 
crops suffer from drought, an effect which we seek to 
arrest by mulching. Drains will keep this soil pul- 
verized, so that water will rise freely by capillary 
attraction, in sufficient quantity for the use of the 
crops. 
It would be impossible, in our limited space, to enu- 
merate the many important details of construction 
that are necessary to insure an active and permanent 
drainage. 
Duties of the agricultural engineer. 
Any kind of work can be executed with greater 
efficiency and economy by a person who has made a 
careful study of the principles involved, and who has 
a thorough knowledge of the details of practical con- 
struction ; and especially in draining, the work of a 
novice is often as expensive as itisclumsy. The 
agricultural engineer should be familiar with all that 
appertains to thorough draining; and it is his duty af- 
ter being called upon by the proprietor, to examine 
the ground, (digging trial holes or a trial drain if neces- 
sary) in order to ascertain the character of the soil as 
to compactness, dip of strata, etc., and also to find 
whether the source of wetness is from beneath by 
springs, or from retention of surface water. If it is 
proposed to drain a large area, a careful topograph- 
