Fig. 20. Shows a No. 6 Pulsometer [capacity 18,000 gallons per hour] throwing a stream 46 feet high through 160 feet of 31⁄2 inch pipe, into a flume on top of the bluff. The pump irrigates 1400 fruit trees, uses about % cord of soft wood per day and is operated by an Indain boy. The plant is in Idaho.

A No. 9 pump, on a lift of 102 feet, used 4 cord of wood in 10 hours and delivered 60,000 gallons per hour. [See page 244.]

LEVELING.

It would require more space, diagrams, and illustrations than can be here given to fully treat of the different kinds of levels, their adjustment, use, and care; and to describe and illustrate the many nice points in the art of leveling. Much of this techincal information may be had from the pamphlets issued by level manufacturers and supplied with the instruments.

Enough will be given to convey to any person of average intelligence so much of a knowledge of the art as is necessary to aid in doing such work as may arise about the farm, and yet such as it would not pay to hire an engineer to do, even if one were to be had at call. The principle of leveling is to reduce the inequalities of the surface to a uniform plane, or to determine the position of a succession of points with reference to a uniform plane.

DATUM PLANE.

It is apparent from this that some plane of reference must be chosen which shall be that to which all other points are referred. Such an arbitrarily selected plane is called the Datum Plane, or plane of reference, and it is assumed to lie at a considerable distance below the surface in order that all points referred to it may have plus (+) elevations, instead of some plus (+) and some minus (-) as would be the case if some portion of the line to be run sank below the level of the datum plane.

In a rough or mountainous country 500 or 1000 feet is taken as the depth of the plane of reference. In this level country 100 feet will be sufficient. That is, in starting any piece of level work assume that the starting point is 100 feet above this plane, or at an elevation of 100; then proceed to get the elevations of all other points, whether higher or lower than the starting point. Before describing the operation of leveling let us very briefly consider the level or leveling instrument.

THE LEVEL.

The engineer's level is a telescopic tube carried in Ys or collars, and having a long level-bubble tube attached, mounted on a horizontally revolving cross-head which is adjusted and maintained in a level or horizontal position by four leveling-screws attached to the head of the tripod on which the instrument rests. Cross hairs in the tube give the exact center and the horizontal line of sight. Such are the main features of a level, and all are constructed on the same general plan.

Some instruments are made with a less powerful and shorter telescope, with fewer parts, lighter weight, and cheaper in price. Levels of this class known as contractors, builders or architects levels are far cheaper than larg

er engineer's levels but they are finely constructed and good for all classes of work.

A still cheaper grade of level is the so called "drainage level" which is made for the express purpose of farm use in laying out drains and ditches. In this special class of instruments there is a wide range of design and price, the latter ranging from $10 to $30. (The manufacturers, Buff and Berger, W. and L. E. Gurley, and Young and Sons, whose advertisements appear herein, are leading makers of the finest instruments and will supply anything in the level line.)

A $25 or $50 instrument will do good work and last a lifetime, if properly cared for. One who can use a level will soon pay the cost of a good one by home-work. If no good level is at hand a simple one, for rough work, may be made out of three pieces of board as shown in Fig. 21.

Take two pieces of narrow board, AB and AC, of exactly equal length and form as shown, and having a span from B to C of 10 feet [one of 161⁄2 foot span-1 rod--may be more convenient.] At exactly equal distances from A, measured along the sides, attach the cross stick D. Fasten on the plumb line and bob P and then adjust the zero point O as follows: Drive two stakes in the ground, as supports for the level, having one of them 2 or 3 ins. higher than the other.

Set the foot C on the higher stake and mark upon D the ex. act point where the line cuts the edge-as at x. Then reverse the level, end for end, so foot B is on the higher stake, and again mark the point where the line cuts D-as at Y. Draw o just midway between these lines. Then whenever the plumb line cuts this o mark the feet B and C are an a level. In one foot a large screw may be set, as shown in the enlarged view at S. When screwed in flush the level is set for level work but when screwed out the level is set for running grades. Thus if a ditch has a fall of 1 foot in 500 feet the screw would be turned out slightly over 14 inch. The level would be set 50 times in the 500 feet (it having 10 foot span.) so of 1 foot would be the grade for each setting.

Such a tool is of course crude but, if well made and skillfully handled, it will yield quite good results. Other simple. home-made levels are frequently described but this is as good as any. Get a good level if possible and learn to do good work with it. It will pay you if you do much irrigating.

The level rod is a rod of dry wood from 8 to 12 feet long, marked into feet, and tenths and hundredths of feet, measuring upward from the bottom of the rod. The rod may have a target or be what is called a "self-reading" rod. The target rod has the graduations cut into the wood and the distances indicated by figures as at A, Fig. 22, the feet in

Fig. 22. Leveling Rods.

LEVELING.

large red figures and the tenths by smaller black figures. The leveler views the cross lines on the target and the rod-man takes the reading as indicated by the target. (In the Fig. the target reads 4 feet)

The self-reading rod needs no target, for the leveler takes the reading from sight at the instrument, the graduations being made visible by painting as shown at B, Fig. 22. Here only the feet are numbered, the smaller graduations not requiring it.

Thus, if the horizontal hair of the level cuts at the following points on the rod the reading would be as follows. Refer to B in the Fig.

The reading to .05 feet being easily made, and, on short sights, a finer reading may be approximated although a reading of less than .05 is not necessary except in very fine work.

Such rods can be easily and accurately made by any intelligent person, and at a cost of not over one dollar. The target may be made of sheet brass or of galvanized iron.

Leveling is very simple work, and the keeping and reduction of level notes equally so. The first thing to do is to set up and level the instrument and to select the HUB or starting point. The form of note-keeping and the order of procedure is shown on the next page. In this sample page from a note-book the following is the significance of the letters heading the several columns. Stn. Station Number; B. S. Back Sight [sometimes called +Sight]; H. I. = Height of Instrument; F. S. = Fore Sight [sometimes called Sight]; Elev. or Ht. = Elevation or height of Station; Rem. Remarks.

The hub, or starting point, which may be any permanent object, or a stake driven for the purpose, is assumed to have an elevation of 100 feet which fact is entered in the note-book as shown. The rod now being held on this hub the line of sight of the instrument, or the plane passing through its center, strikes the rod 4 feet from the bottom. Enter this under B. S. as shown. Now if the hub is 100 feet and the instrument reads 4 feet above it. the center of the instrument is evidently on a plane or level of 104 feet [so that Elev. added to B. S. = H. I. or 104 ft.] The H. I. being known the height of any other point is found thus. The rodman goes to station 1 and the leveler reads a F. S. of 5.20, which he enters as shown under F. S.

If the instrument is on a level of 104 ft., and the reading on the rod at Stn. 1 is 5.20, it is evident that Stn. 1 is 5.20 ft. lower than the instrument. The level of Stn. 1 is therefore found by merely subtracting the F. S. reading on that Stn. (5.20) from the H. I. (104) 98.80-which enter as shown. In like manner readings are taken at Stns. 2 and 3 which result as shown in the notes. From where the instrument now stands stn. 4 cannot be seen so the level is moved to a new position from which stns. 4 and 5 may be seen. Set up and adjust as before.

The rodman having staid at Stn. 3 the leveler now takes a B. S. reading on that point. The reading of 7.35 is entered as a B. S. Stn. 3 (T. P., or turning point) having an Elev. of 96.45 and the B. S. equaling 7.35 their sum, or 103.80, will give a new H. I. or plane of reference.

Before proceeding to take the level of Stn. 4 the leveler deems it best to take level on some new hub so that in case the original hub is moved or destroyed he can relocate his work from the new hub. The rodman sets up on the barn floor and the leveler reads 8.80 which substracted from 103.80 =95 as the Elev. of the barn floor.

He then proceeds as before to take the elevations of other stations and to set such other hubs as he may desire. From this explanation may be drawn the whole secret of leveling and note keeping.

The Elev. of any starting point added to the B. S. reading on that point give the H. I. and any F. S. reading subtracted from the H. I. gives the Elev. of the point on which the reading is taken. Any number of F. S. readings may be taken from one setting of the instrument so long as the range of sight is clear. Thus, the instrument may be set at or near the center of a reservoir and the levels taken at all points about the bank without moving.

Aim, however, to have the lengths of B S and F S courses as nearly equal as possible in order not to magnify any slight error in the adjustment of the instrument.

Note especially one fact-as the grade or level runs down the target or reading runs up on the rod; that is, it takes a greatar length of rod to reach from the plane of the instru