592 EXPERIMENT STATION RECORD. 



the results of comparative service tests of these and other asphalt" pavements it 

 is stated that although the percentage of bitumen in the Oklahoma rock asphalt 

 is less than that in the sheet asphalt it is as great as that of the rock-asphalt 

 pavements of Europe, which have given satisfaction for years. 



It is concluded that pavements constructed of Oklahoma asphalts are suc- 

 cessful and that these asphalts are worthy of consideration as a paving 

 material. 



A new 2-cycle internal-combustion eng'ine, G. Lecointre (Bui. Soc. Agr. 

 France, 1913, May 15, Sup., pp. 678-680, fig. 1). — A 2-cylinder, 2-cycle internal- 

 combustion engine is described in which the charge of gas for each cylinder is 

 supplied by the compression stroke of the piston in the other cylinder, thus 

 avoiding the necessity of each cylinder's being charged by the suction stroke of 

 its own piston at the same time the burned gases are exhausted. Bach piston 

 has a raised portion before the inlet which deflects the gas to the top of the com- 

 bustion chamber, thus forcing the burned gas out at the exhaust below. This 

 arrangement of 2-cycle engine is claimed to be much more simple, efficient, and 

 economical than the ordinary arrangement, and is said to be practically as 

 efficient as a 4-cylinder 4-cycle engine of the same size, and of much greater fuel 

 economy. Two tests are reported, in the first of which it is claimed that 43 h. p. 

 were developed at 1,250 r. p. m. with a fuel consumption of 340 gm. per horse- 

 power hour, and in the second 26 h. p. at 920 r. p. m. with a fuel consumption of 

 390 gm. per horsepower hour. 



A note on steam plowing', A. A. MusTO {Dept. Agr. Bombay Bill. 5Jf, 1912, 

 pp. 11+50, pis. Jf). — This bulletin deals with mechanical plowing outfits as re- 

 gards their adoption in the Bombay Presidency. Detailed descriptions and 

 sketches are given of 5 general sy.stems, viz. (1) the direct traction system; (2) 

 direct cable-di"awn implements on the double-engine system; (3) indirect cable- 

 drawn implements on the roundabout system with a traction engine fitted with 

 winding drums; (4) indirect cable-drawn implements but with a portable engine 

 driving a separate windlass; and (5) direct cable-<lrawn implements worked 

 with bullock geared windlasses. The various conditions of soil, vegetation, and 

 atmosphere in the Bombay Presidency are described as favorable to the prof- 

 itable application of mechanical cultivation, particularly for the eradication of 

 hariali grass, for which it is necessary to turn up the soil to a depth of at least 

 16 in. A badly infested area of 14 acres was plowed 14 to 16 in. deep. The 

 work was started in January and finished in April, and by August the crop was 

 looking remarkably well and the hariali grass was practically extinct. 



From various service tests and operations statements of the advantages and 

 disadvantages of each system are made with estimates of the capital outlay, the 

 annual working expenses, and the cost per acre plowed for each system. The 

 total capital outlay for an outfit of the first class, consisting of an SO h. p. en- 

 gine, balance plow, cultivator, and harrow, is estimated at 21,300 rupees (about 

 $6,900), and the annual working expenses at 8,650 rupees. With this outfit 

 plowing by direct traction it is not possible to plow to a depth of more than 

 8 or 9 in. in black cotton soil, but it is estimated that with 2 shifts of men this 

 engine will plow 8 acres per day of 14 hours to a depth of 8 in. at an average 

 cost per acre of 8 rupees and 5 annas (about $2.60). 



The total capital outlay for an outfit of the second type, consisting of two 80 

 h. p. engines, plow, cultivator, and harrow, is estimated at 40.500 rupees, and the 

 annual working expenses at 15.125 rupees. It is estimated that this outfit with 

 2 shifts of men will plow in black cotton soil 8 acre'? per day to a depth of from 

 ] 6 to 18 in. at an average cost per acre of 14 rupees and 8 annas. When plow- 

 ing at a depth of 8 or 9 in. with this outfit the cost per acre is estimated at 5 

 rupees and 13 annas (about $1.90). 



