Commencing at the southwest corner of the field, and measuring toward the east a distance of 34 feet, set a pole to indicate the position of the outlet. Next, mark the center of the silt-basin at the proper point, which will be found by measuring 184 feet up the western boundary, and thence toward the east 96 feet, on a line parallel with the nearest row of 50-foot stakes. Then, in like manner, fix the points _C1_, _C6_, _C9_, _C10_, and _C17_, and the angles of the other main lines, marking the stakes, when placed, to correspond with the same points on the map. Then stake the angles and the upper ends of the laterals, and mark these stakes to correspond with the map. It will greatly facilitate this operation, if the plan of the drains which is used in the field, from which the horizontal lines should be omitted, have the intersecting 50-foot lines drawn upon it, so that the measurements may be made from the nearest points of intersection.(14) Having staked these guiding points of the drains, it is advisable to remove all of the 50-foot stakes, as these are of no further use, and would only cause confusion. It will now be easy to set the remaining stakes,—placing one at every 50 feet of the laterals, and at the intersections of all the lines. A system for marking the stakes is indicated on the map, (in the _C_ series of drains,) which, to avoid the confusion which would result from too much detail on such a small scale, has been carried only to the extent necessary for illustration. The stakes of the line _C_ are marked _C1_, _C2_, _C3_, etc. The stakes of the sub-main _C7_, are marked _C7a_, _C7b_, _C7c_, etc. The stakes of the lateral which enters this drain at _C7a_, are marked _C7a/1_, _C7a/2_, _C7a/3,_ etc. etc. This system, which connects the lettering of each lateral with its own sub-main and main, is perfectly simple, and avoids the possibility of confusion. The position of the stakes should all be lettered on the map, at the original drawing, and the same designating marks put on the stakes in the field, as soon as set. _Grade Stakes_, (pegs about 8 or 10 inches long,) should be placed close at the sides of the marked stakes, and driven nearly their full length into the ground. The tops of these stakes furnish fixed points of elevation from which to take the measurements, and to make the computations necessary to fix the depth of the drain at each stake. If the measurements were taken from the surface of the ground, a slight change of position in placing the instrument, would often make a difference of some inches in the depth of the drain.