488 EXPERIMENT STATION EECORD. 



eiencies of 78, 68.5, and 48.9 per cent, and on the basis tliat tlie motor should 

 develop the average maximum power necessary multiplied by 1.75 (E. S. R., 

 29, p. 185), these systems will require respectively one 30 to 35 horsepower 

 motor, two 35 to 40 horsepower motors, and one 50 horsepower motor. 



Motor cultivation, its practical applications, T. Ballu (La Motoculture, ses 

 Applications Pratiques. Paris [1913], pp. 290, figs. 19; rev. in Ann. 8ci. Agron., 

 4. sen, 3 (1914), No. 2. pp. 110, 111). — The main purpose of this book is to pre- 

 sent the principles underlying the construction in the more recent developments 

 in mechanical cultivating machinery. Their cost and economic application are 

 also treated as prime considerations. 



On the history of horseshoeing-, J. Hobn ( TJeher den dltesten Hufschutz des 

 Pferdes. Inmig. Diss., Univ. Leipsic, 1912, pp. 83). — ^A treatise on the history 

 and development of the art of horseshoeing since the earliest recorded history. 

 A list of 84 references is appended. 



Test of some joints used in heavy timber framing, H. D. Dewell (Engvn. 

 News, 71 (1914), Nos. 12, pp. 593-598, figs. 9; 13, pp. 666-669, figs. 5).— Tests 

 on pin-keyed, lag-screwed, and bolted timber joints and tests of washers are 

 reported. 



White oak, Australian hickory, and gas pipe pins were rejected as unsuitable 

 material for pin-keyed joints. Extra heavy wrought steel pipe was practically 

 as efficient as solid metal for pins, but the Hawaiian hard wood Ohia pins gave 

 a higher resistance than either. In lag-screwed joints it is believed that the 

 resistance of the screw is appreciably the same whether it bears against or 

 across the grain of the main timber. " In the case of a metal plate lag-screwed 

 to timber. . . . the strength would be determined by the strength of the 

 screw in shear, or the plate in bearing." 



Washer tests, by F. L. Bixby, showed the fallacy of using the ordinary 

 washers with bolts or rods in which considerable tension exists. Other tests 

 showed a great variation in the strength of different washers of the same size. 

 The J-in. and |-in. washers were less efficient than those of larger diameter. 



For permanent work it is recommended that washers be given an area to 

 provide bearing across the fibers of Douglas fir at a stress of 285 lbs. per 

 square inch when the stress in the bolt is 16,000 lbs. per square inch, and that 

 no thickness of metal be less than one-quarter inch. 



Anchoring houses in overflow districts, B. Younublood (Texas Sta. Giro. 

 2, n. ser. (1914), PP- 8, figs. 2). — Plans, specifications, and bills of material for 

 two kinds of foundations or piers to be used in anchoring houses in the river 

 bottoms, prepared by A. INIitchell, are given. 



Beef cattle and sheep barns, R. S. Curtis (North Carolina Sta. Circ. 2, rev., 

 (1914), pp. 21, figs. 13). — This circular gives several ground plans, accom- 

 panied by descriptive information, of beef cattle and sheep barns, and is in- 

 tended to cover the conditions existing on the various farms in the State where 

 sheep and cattle are maintained. 



In planning a cattle or sheep barn it is pointed out that provision should be 

 made for the probable yearly increase in the number of animals, and that the 

 barn should be so arranged that an extension may be conveniently made. The 

 author advocates the construction of a two-story or loft barn as being better 

 adapted to the needs of the general live-stock farmer. For beef fattening 

 cattle he advocates the use of a barn large enough to house the cattle com- 

 fortably, thus saving the manure and avoiding the use of an excessive amount 

 of bedding. " Each steer should be provided with at least 50 sq. ft. of space in 

 a closed barn, which with a 10-ft. elevation, allows 500 cu. ft. of air space 

 per animal. In an open barn this provision is not so important, yet it is 



