140 THE APPLE 



shown in Figs. 61 and 62. A 2-inch fall to every 100 feet may 

 be regarded as a suitable grade for head flumes, but it often hap- 

 pens that the slope of the land is much greater than this, in which 

 case low checks are placed in the bottom of the flume at each 

 opening, as shown in Fig. 62. 



A head flume composed of cement, sand, and gravel costs, as 

 a rule, about twice as much as a wooden flume of the same capacity, 

 but the early decay of wood, especially if it comes in contact with 

 earth, makes the cement flume cheaper in the end. By means of 

 a specially designed machine, which is patented, cement mortar 

 composed of 1 part cement to about 6 parts coarse sand is fed 

 into a hopper and forced by lever pressure into a set of guide plates 

 of the form of the flume. Such flumes are made in place in one 

 continuous line across the upper margin of the orchard tract. After 

 the flume is built and before the mortar has become hard, small 

 tubes from | inch to i| inches in diameter — the size depending 

 somewhat on the size of the flume — are inserted in the side next 

 to the orchard. The flow through these tubes is regulated by zinc 

 slides, as shown in Fig. 62. Flumes of this kind are made in 

 five sizes, the smallest being 6 inches on the bottom in the clear 

 and the largest 14 inches. 



At a slightly greater cost a stronger flume can be built by the 

 use of molds. The increased strength is derived from a difference 

 in the mixture. In the machine-made flume the mixture of 1 part 

 cement to 5 or 6 parts sand is lacking in strength, for the reason 

 that there is not enough cement to fill all the open spaces in the 

 sand. In using molds medium-sized gravel is added to the sand, 

 and the result is a mixture that resembles the common rich con- 

 crete. These flumes can be built of almost any size, from a bottom 

 width of 10 inches to one of 40 inches and from a depth of 8 inches 

 to one of 24 inches, but when the section is increased beyond about 

 240 square inches, it is better to slope the sides outward and adopt 

 the form of the cement-lined ditch. At present the cost of rich 

 concrete in place would be about $9.00 per cubic yard for the larger 

 flumes and $10.50 for the smaller sizes. In ascertaining the 

 quantity of concrete required in each linear foot of flume, it will be 

 necessary to know exactly the size and thickness of the sides and 

 bottom of the flume. In reality the amount depends on these factors. 



