RURAL ENGINEERING. 791 



should have a ring at its lower extremity, in addition to the usual piston 

 rings, to create a pressure to force oil accumulations to the wrist-pin bearings 

 rather than to the combustion chamber. He points out the evils of the splash 

 and flushing systems of lubrication and advocates the automatically regulated 

 pressure pump system used in most foreign designs. He discusses the fire, 

 cold, and viscosity tests of oils, and states that a high-fire test, fairly thin oil 

 is best adapted to vertical engines using a positive force-feed lubrication sys- 

 tem, while a low-fire test oil better answers the requirements where splash 

 systems are employed, on account of allowing for a sure sufficiency for a less 

 positive system in order that the excess oil may be more completely consumed 

 in the combustion chamber. 



Cooling the farm, engine, J. H. Beattie (Farm Machinery, 1912, No. 1072, 

 pp. 15, IG). — Attention is called to the importance of keeping the cylinder of a 

 gasoline engine cool, and several farm engines are described which are cooled 

 by air, water, or oil. 



A gas locomobile, L. Dubois (Jour. Agr. Prat., n. ser., 23 {1912), No. 21, pp. 

 6o.'i, 655, ftg-s. 2). — A description is given of a power and tractor outfit consisting 

 of a combination of internal combustion engine and gas generating equipment. 

 The engine is a 4-cycle, water cooled type manufactured in sizes of from 8 to 

 55 horsepower, and burns the gas direct from the attached generator. 



Problem of the small tractor, L. W. Ellis (Farmer\<i Advocate, //7 (1912), 

 No. 1032, pp. 960, 901, figs. .'/). — This is a paper read before the National Gas 

 Engine Trades Association at Milwaukee. 



The author discus.ses the small tractor problem confronting tractor designers 

 and compares American with foreign design. The French designers have dealt 

 most extensively with small, all-service tractors, and combinations of tractor 

 engine with plowing and cultivating devices, with indifl'erent success, while the 

 Americans have dealt almost exclusively with large tractors for heavy work. 

 " rractically every idea submitted abroad has been the subject of original 

 investigation and experiments in this country, and actual experience has shown 

 the impracticability of many of what ai'e superficially regarded as essentials of 

 the small tractor." 



Why a kerosene tractor, II. Olney (Irrig. Age, 21 (1912), No. 10, pp. 372, 

 373, figs. Jf ) . — A discussion of the fuel question for internal combustion tractors, 

 giving a comparison of the costs of using gasoline and kerosene in a special 

 type. With this tractor plowing was done with gasoline for 72.6 cts. per acre 

 and with kerosene for 58.6 cts. per acre. 



Can tractor rating be standardized? (Canad. TliresTicrmfin and Farmer, 17 

 (1912), No. 7, pp. -}.J6, 4^c). — A discussion of the problem of a standard system 

 of rating for tractors. One opinion expressed is that since a tractor is required 

 to operate under widely varying conditions of soil, roadway, and weather, a 

 conservative brake horsepower rating of 20 per cent below the possibly developed 

 brake horsepower should be adopted, while another opinion is that a standard 

 method of testing could be adopted requiring the use of a pair of drums mounted 

 on a shaft running on roller bearings and connected to a Prony brake. The 

 tractor should be made to climb planks into such a position that the traction 

 wheels would be in contact with and supported by the drums and held in this 

 position by a draw-bar dynamometer connected to a post. By this apparatus 

 and by scales under the front wheels and the draw-bav dynamometer, the load 

 on the traction w'heels when pulling and at rest, giving the axle torque and 

 the horsepower delivered, including rolling friction of the tires, and readings 

 in connection with the traction-wheel tire speed, can be obtained. 



Motor plows and ground-breaking machinery, Holldack (Jalirh. Dent. 

 Landao. Gesell., 21 (1912), No. 1, pp. 203-219, pU, 15, figs. 11). — A discussion is 



