EURAL ENGINEEEITTG. 893 



grinders, grindstones, cream separators, line shafting, steam boilers and engines, 

 and internal combustion and electric motors. 



Facts and figures on the oil tractor for the farm, A. G. Barnet {Gas Engine, 

 15 (1913), No. 7, pp. 379-381, figs. 5).— Tests on level ground gave the following 

 drafts per square inch of cross section of plow, the cross section being taken 

 equal to the plow width times the depth plowed: Sandy soil, 3 lbs.; clay soil, 

 S lbs. ; clover sod, 7 lbs. ; virgin sod, 15 lbs. ; prairie sod. 15 lbs. ; and gumbo soil, 

 20 lbs. It is said that each 1 per cent rise in grade ndds 1 per cent of the weight 

 of the tractor and plows to the draft. 



The theory of centrifugal pumps, R. L. Daxjgherty (Poicer, SS (WIS), No. 

 S, pp. 79-83, figs. 10). — This article discusses the various divisions of head 

 entering iuto the operation of a centrifugal pump and deals both mathematically 

 and graphically with the characteristics of both turbine and volute pumps. 



Test of a two-stage turbine pump, A. A. Potter and W. W. Carlson (Power, 

 SS (1913), No. S, p. 83). — ^A two-stage turbine pump was tested on an irrigation 

 project in western Kansas at an elevation of 2,850 ft. Water was found at a 

 depth of 65 ft. but in order to eliminate some of the difficulties encountered the 

 pump was set at a depth of 123 ft. Power was supplied by a 16X24 single 

 cylinder, 4 cycle oil engine, using a 42° B. oil. The pump was run at nearly 

 800 r. p. m. during the test and the water was measured by means of a trape- 

 zoidal weir, all measurements being checked with a pilot tube. 



The resulting data indicate that for every gallon of fuel used, 5,400 gal. of 

 water was pumped, or with oil at 3 cts. per gallon, 1,800 gal. for 1 ct. There 

 was pumped per minute 617.5 gal. of water at an expense of about J ct. 



Test of a row and broadcast seed drill, E. Gieseleb (Maschinen Ztg., It 

 (1913), No. 1, pp. 1, 2, figs. 8). — The drill has 11 seed droppers and has a work- 

 ing width of 2 meters. It was first calibrated by means of an electric motor 

 which operated the mechanism at an approximate speed of 3 ft. per second. 

 It was then operated on both level and hilly land, the seed used being wheat, 

 rye, oats, corn, beet seed, beans, and peas. 



The seeds were sown without injury. It was found that on level ground the 

 machine sowed within 1.3 to 1.7 per cent of the requiretl amount of wheat, rye, 

 and oats; within 1.9 to 2.9 per cent of the required amount of corn; and 

 within 2.9 to 3.48 per cent of the required amount of beet seeds and peas. 

 The total quantity of seed sowed increased on an upgrade and decreased on a 

 downgrade, the increase or decrease for each per cent rise or faU in grade being 

 for wheat, rye, oats, and corn, respectively, 0.15, 0.28, 0.31, and 0.95 per cent. 

 In comparison with several other seed drills tested this driU gave the best 

 distribution of seed. 



It is concluded that this drill is fitted for both flat and hilly land. It is in 

 all parts very durable, the operation is simple, and the adjustments may be 

 made in less than a minute. It is very accurate in amount of seed sowed and in 

 seed spacing. 



Steam pipes in dairies (Molk. Ztg. [HUdesheim], 27 (1913). No. 12, pp. 219, 

 220). — Attention is called to the important points in the installation of steam 

 pipe systems in dairies, dealing with saturated, superheated, and exhaust steam. 

 Tables of data are given relative to steam pipe sizes for various boiler pres- 

 sures and amounts of steam consumed, expansion of steam pipes, and con- 

 densation losses. 



Electrical engineer's pocketbook, H. A. Foster (New York, 1913, 7. ed., rev., 

 pp. XXXVI+1599, illus.). — This is a handbook of useful data for electricians 

 and electrical engineers. 



