90 



QUARTERLY J0UR:«AL 



a.a. Side stones. 



b. Keystone. 



c. Water course. 



d. Filling of stones. 



6. Covering of soda. 

 /. Filling of earth. 

 g. Covering of earth. 



After the keystones are in, I proceed to put in the largest of 

 those which are on hand ; but there is this to be observed, that the 

 flattest stones, and the larger their surface the better, so they be 

 not too high, are first selected and placed with their flattest sides 

 against the sides of the ditch to keep the banks to their places, 

 and then of the stones that are thrown in promiscuously care 

 should be taken to have them lie as level as may be, with their 

 flattest sides up to intercept earth in its passage down ; the nearer 

 we come to the top the smaller the stones should be, and break 

 joints with them as much as possible, and my practice is to break 

 some on the top of the filling with a hammer, to the end that 

 every crevice may be filled up. Then invert the sods upon them, 

 and last of all with a road scraper, scrape on the loose earth and 

 round it up over the drain. 



In this section of country we sometimes have severe frosts with- 

 out a covering of snow on the earth to prevent its getting in 

 deep. Sometimes it freezes to the depth of two feet or more ; and 

 I see no reason why it should not work upon, and loosen the sur- 



