A general purpose portable kerosene engine is admirably suited to all work requiring considerable horsepower and long hours of service with a fairly steady load, such as tractor work, threshing, custom feed grinding, irrigating and silo filling. There will be a considerable saving in fuel bill over a gasoline engine if the engine will really run with kerosene, or other low-priced fuel, without being mixed with gasoline. In choosing a kerosene engine, particular attention should be paid to whether or not the engine can be run on all loads without smoking. Unless this can be done, liquid fuel is entering the cylinder which will cause excessive wear on the piston and rings. A good kerosene engine should show as clean an exhaust as when operating on gasoline and should develop approximately as much horsepower. Another feature is harmonizing the fuel oil and the lubricating oil so that one will not counteract the effects of the other. PORTABLE FARM ENGINE AND TRUCK [Illustration: Figure 111.--Portable Farm Engine. This engine is permanently mounted on a low wheel truck wagon. The saw frame is detachable and the same truck is used for spraying and other work.] A convenient arrangement for truck and portable power for spraying, sawing wood and irrigation pumping, is shown in the accompanying illustration. The truck is low down, which keeps the machinery within reach. The wheels are well braced, which tends to hold the outfit steady when the engine is running. The saw table is detachable. When removed, the spraying tank bolts on to the same truck frame; also the elevated table with the railing around it, where the men stand to spray large apple trees, is bolted onto the wagon bed. Spraying never was properly done until the powerful engine and high pressure tanks were invented. Spraying to be effective, should be fine as mist, which requires a pressure of 150 pounds. There may be a number of attachments to a spraying outfit of this kind. A pipe suspended under the frame with a nozzle for each row is used to spray potatoes, strawberry vines and other low down crops that are grown in rows. When not in use as a portable engine it is blocked firmly into place to run the regular stationary farm machinery. HYDRAULIC RAM