The speed requirements of machines are given by the manufacturers. It is up to the farmer to determine the size of pulleys and the speed of intermediate shafts between his engine and the machine to be driven. A speed indicator is held against the end of a shaft at the center. The indicator pin then revolves with the shaft and the number of revolutions per minute are counted by timing the pointer on the dial with the second hand of a watch. [Illustration: Figure 182.--Speed Timers. Two styles. The point is held against the center of the shaft to be tested. The number of revolutions per minute is shown in figures on the face of the dial. The indicator is timed to the second hand of a watch.] [Illustration: Figure 183.--Building Bracket. Made of 2 x 4 pieces put together at right angles with diagonal braces. The supporting leg fits between the four diagonal braces.] SOIL TOOLS Soil moisture often is the limiting factor in crop raising. Soil moisture may be measured by analysis. The first step is to obtain samples at different depths. This is done accurately and quickly with a good soil auger. Other paraphernalia is required to make a careful analysis of the sample, but a farmer of experience will make a mud ball and form a very good estimate of the amount of water in it. [Illustration: Figure 184.--Diagram showing how to cut a plank on a band-saw to form a curved rafter. The two pieces of the plank are spiked together as shown in the lower drawing. This makes a curved rafter without waste of material.] [Illustration: Figure 185.--Breeding Crate for Hogs. The illustration shows the manner of construction.] [Illustration: Figure 186.--Soil Auger. Scientific farming demands that soils shall be tested for moisture. A long handled auger is used to bring samples of soil to the surface. The samples are weighed, the water evaporated and the soil reweighed to determine the amount of moisture.] [Illustration: Figure 187.--Post Hole Diggers. Two patterns of the same kind of digger are shown. The first has iron handles, the lower has wooden handles.] [Illustration: Figure 188.--Hoes and Weeders. The hang of a hoe affects its working. The upper hoe shows about the easiest working angle between the blade and the handle. The difference between a hoe and a weeder is that the hoe is intended to strike into the ground to loosen the soil, while the blade of the weeder is intended to work parallel with the surface of the soil to cut young weeds.] [Illustration: Figure 189.--Manure Hook and Potato Diggers.] [Illustration: Figure 190.--Spud. Certain vegetables are grown for crop and for seed. The green plants are thinned with a spud for sale, leaving the best to ripen for seed. It is also used to dig tough weeds, especially those having tap roots.] [Illustration: Figure 191.--(1) Corn Cutting Knife. (2) Asparagus Knife.] FENCE-MAKING TOOLS