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8th. Multiply the numbers of the second column by those of the third and divide the product by 100. The result will be the amount of fall be. tween the stakes, (fourth column.)-Example: 1.87 × 82=153+100=1.53.

9th. Subtract the first number of the fourth column from the first number of the fifth column, (on the line above it,) and place the remainder on the next line of the fifth column.-Example: 20.70—1.64= 19.06.

Then, from this new amount, subtract the second number of the fourth column, for the next number of the fifth, and so on, until, in place of the entry in pencil, (Stake 3,) we place the exact result of the computation.

Proceed in like manner with the next interval,-3 to 7.

10th. Subtract the numbers in the sixth column from those in the fifth, and the remainders will be the depths to be entered in the last. Under the head of "Remarks," note any peculiarity of the drain which may require attention in the field.

The main lines A, D, and E, and the drain B, should next be graded on the plan set forth for C, and their laterals, all of which have considerable fall, and being all so steep as not to require silt-basins at any point, can, by a very simple application of the foregoing principles, be adjusted at the proper depths. In grading the stone and tile drain, (H, I,) it is only necessary to adopt the depth of the last stakes of the laterals, with which it is connected, as it is immaterial in which direction the water flows. The ends of this drain,-from H to the head of the drain C10, and from I to the head of C 17,-should, of course, have a decided fall toward the drains.

The laterals which are placed at intervals of 20 feet, over the underground rock on the east side of the field, should be continued at a depth of about 3 feet for nearly their whole length, dropping in a distance of 8 or 10 feet at their lower ends to the top of the tile of the main. The intervals between the lower ends of C7c, C7d, and C7e, being considerably more than 20 feet, the drains may be gradually deepened, throughout their whole length from 3 feet at the upper ends to the depth of the top of the main at the lower ends.

The main drains Fand G, being laid in flat land, their

outlets being fixed at a depth of 3.50, (the floor of the main outlet,) and it being necessary to have them as deep as possible throughout their entire length, should be graded with great care on the least admissible fall. This, in ordinary agricultural drainage, may be fixed at .25, or 3 inches, per 100 feet. Their laterals should commence with the top of their tile even with the top of the 24 collar of the main,-or .15 higher than the grade of the main, —and rise, at a uniform inclination of .25, to the upper end.

Having now computed the depth at which the tile is to lie, at each stake, and entered it on the map, we are ready to mark these depths on their respective stakes in the field, when the preliminary engineering of the work will be completed.

It has been deemed advisable in this chapter to consider the smallest details of the work of the draining engineer. Those who intend to drain in the best manner will find such details important. Those who propose to do their work less thoroughly, may still be guided by the principles on which they are based. Any person who will take the pains to mature the plans of his work as closely as has been here recommended, will as a consequence commence his operations in the field much more understandingly. The advantage of having everything decided beforehand, so that the workmen need not be delayed for want of sufficient directions, and of making, on the map, such alterations as would have appeared necessary in the field, thus saving the cost of cutting ditches in the wrong places, will we'l repay the work of the evenings of a whole winter.

CHAPTER IV.

HOW TO MAKE THE DRAINS.*

Knowing, now, precisely what is to be done; having the lines all staked out, and the stakes so marked as to be clearly designated; knowing the precise depth at which the drain is to be laid, at every point; having the requisite tiles on the ground, and thoroughly inspected, the operator is prepared to commence actual work.

He should determine how many men he will employ, and what tools they will require to work to advantage. It may be best that the work be done by two or three men, or it may be advisable to employ as many as can work without interfering with each other. In most cases,especially where there is much water to contend with,—the latter course will be the most economical, as the ditches will not be so liable to be injured by the softening of their bottoms, and the caving in of their sides.

The Tools Required are a subsoil plow, two garden lines, spades, shovels, and picks; narrow finishing spades, a finishing scoop, a tile pick, a scraper for filling the ditches, a heavy wooden maul for compacting the bottom filling, half a dozen boning-rods, a measuring rod, and a plumb rod. These should all be on hand at the outset, so that no delay in the work may result from the want of them,

Writers on drainage, almost without exception, recom. mend the use of elaborate sets of tools which are intended * The instructions given in this Chapter are somewhat modified by newer processes, which are described in the Supplemental Chapters, especially Chapter XIII. These should be well noted.-(Note to 2d edition.)

B

Fig. 22.-SET OF TOOLS.

Flat Spades of various lengths and widths, Billnecked Scoop (A); Tile layer (B); Pick-axe (C); and

Scoop Spades, and

Shovel.

for cutting very narrow ditches,-only wide enough at the bottom to admit the tile, and not allowing the workmen to stand in the bottom of the ditch. A set of these tools is shown in Fig. 22.

Possibly there may be soils in which these implements, in the hands of men skilled in their use, could be employed with economy, but they are very rare, and it is not believed to be possible with unskilled laborers to regulate the bottom of the ditch so accurately as is advisable, unless the workman can stand directly upon it, cutting it more smoothly than he could if the point of his tool were a foot or more below the level on which he stands.

On this subject, Mr. J. Bailey Denton, one of the first draining engineers of Great Britain, in a letter to Judge French, says:

"As to tools, it is the same with them as it is with the "art of draining itself,-too much rule and too much draw"ing upon paper; all very right to begin with, but very "prejudicial to progress. I employ, as engineer to the "General Land Drainage Company, and on my private "account, during the drainage season, as many as 2,000 66 men, and it is an actual fact, that not one of them uses "the set of tools figured in print. I have frequently pur"chased a number of sets of the Birmingham tools, and "sent them down on extensive works. The laborers would 66 purchase a few of the smaller tools, such as Nos. 290, "291, and 301, figured in Morton's excellent Cyclopædia "of Agriculture, and would try them, and then order "others of the country blacksmith, differing in several respects; less weighty and much less costly, and more over, much better as working tools. All I require of the cutters, is, that the bottom of the drain should be evenly cut, to fit the size of the pipe. The rest of the work "takes care of itself; for a good workman will economize "his labor for his own sake, by moving as little earth as "practicable; thus, for instance, a first-class cutter, in

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