534 [.\SSEMBL1 



8. When it is impossible to malie the drain sufficiently deep on 

 account of level, use the auger to tap the spring. 



In regard to the constru'^tion of drains, attention may be called 

 to the following points : 



1. The direction of drains; they should always run down the 

 steepest descent, and parallel to each other ; by observing this 

 rule, the water has the shortest way to percolate in reaching the 

 drain, and consequent early delivery into the drain; both points 

 of great importance. It has been argued that drains should be 

 directed in an oblique form, but practice now uniformly favors the 

 straight down hill direction. The direction of the mains depends 

 entirely upon the value of the ground and levels. When the sur- 

 face is undulating, the rule is to lay a main of sufficient size along: 

 the principal hollow, with sub-mains along all the secondary hol- 

 lows, the small mains opening into these at right angles. 



2. The frequency of small drains. The distance at which the 

 small drains are placed apart depends on several circumstances, 

 such as the texture of the soil, the depth of the drains, and whe- 

 ther it is only surface water that they have to deliver. A drain 

 that has eighteen inches sectional capacity, when running half full 

 at the outlet, will discharge in twenty-four hours, six hundred 

 tons of water, equal to a rain fall of nearly six inches in depth on 

 an acre. One inch in depth is a very heavy fall in a day, and it 

 usually tf kes two days for the water, after rain, to drain entirely 

 from land deeply drained. Eighteen such drains on an acre, 

 would discharge when half filled four and a half inches of a rain 

 fall from the same in one hour, and in six hours more than a 

 whole atinual fall of rain. Still, through the ignorance of the 

 owners, lands have been so drained. The condition of lands 

 throughout districts in the suburbs of cities and towns should be 

 •examined by means of test holes, as explained at the last meeting 

 of the club. The information obtainable by this means consists of 



1. A knowledge of the nature of the lana in a district, and its 

 capabilities. 



2. The state of each district as to drainage, or the want of it. 



