AGRICULTURAL ENGOEERING. 623 



Experiments with electrical plow installations, M. Schiller [Arb. Deut. 

 Landv. (JeselL, I90.i, Xu. 85, pp. 70, Jiijx. 4^1) ■ — Three series of field trials of double- 

 motor systems are reported, the apparatus and machines used l)eing described in 

 detail. The power was sup[)lied from a central plant and the tests included deep 

 plowing (80 to 36 cm.) on heavy soils and shallow plowing (14 to 18 cm.) on light 

 soils, the object being to secure data on rapidity of work, amount of soil moved, 

 loss of power, cost, and time required to move from field to field. The results are 

 not co'nsidered conclusive and further tests are recommended. 



The Scott motor cultivator {Queensland Agr. Jour., 13 {1903)., No. 4, pp. 316, 

 317, fig. 1). — A petroleum motor adapted to a variety of farm operations is described 

 and a comparison is made of the efficiency of motor and horse cultivation. 



Agricultural implements and vehicles in foreign countries ( U. S. Con.mlar 

 Rpts., 73 {1903), No. 279, pp. 720-742). — This is a series of reports in continuation of 

 those already noted in the Record (E. S. R., 15, p. 416). The countries reported 

 on in this artii'lc are Denmark, Kritish India, rruguay, and Honduras. 



Roads; their construction and maintenance, with special reference to road 

 materials, A. Greenwell and J. V. Elsden {London: D. Fourdrinier, 1901, pp. 280, 

 figs. 4^). — An elementary treatise suited especially to English conditions. 



An essay on the history of rural engineering, M. Ringelmann {Ann. Inst. 

 Nat. Agron., 2. ser., 2 {1903), No. 2, pp. 181-21 J, figs. 22). — The development of rural 

 engineering during the prehistoric period is briefly traced in this article. 



[The octagonal silo], A. T. Neale {Delaimre Sta. Rpt. 1902, pp. 30-35). — The 

 methods and cost of construction as well as the practical advantages of octagonal 

 silos are discussed. 



"The octagonal silo may be regarded as a compromise between the old style 

 square shaped, heavily framed or thick walled stone form and the modern lightly 

 constructed stave silo, circular in shape and bound by iron hoops." The experience 

 on a number of farms in Delaware with silos of this type constructed upon plans and 

 specifications furnished by the station is cited to show that such silos have proven 

 very satisfactory in practice, and as regards cost, availability of material, ease of con- 

 struction, durability, and efficiency possess many decided advantages. 



The construction of such a silo 13 ft. from face to face and 22 ft. deep, having a 

 capacity of 68 tons when properly filled with settled corn and cowpea silage, is thus 

 briefiy described : 



"If eight pieces of seasoned white oak, each 3 in. thick, 6 in. wide, and 6 ft. long, 

 are so placed as to form a regular eight-sided figure with the corners bolted together, 

 the sill of the silo will have been formed, and this drawn down into soft cement by 

 the corner bolts which extend into the masonary foundation 10 in. will make an air- 

 tight base. Posts of black or red oak, each 3 in. thick, 6 in. wide, and 18 in. tall are 

 set upright at each of the eight corners of this sill and firmly spiked to it; upon the 

 top of said posts a second eight-cornered hoop of black or red oak, but in all other 

 respects similar to the sill, is built. Seven similar hoops are in turn built one upon 

 the other, upon posts which increase in length as the height of the structure 

 increases, until the posts which bear the plate are reached and these may safely 

 measure 3 ft. in length. These hoops may be compared with those which bind 

 together the staves of a barrel. 



"In the silo the staves are of inch boards, 1 ft. wide, firmly nailed both to 

 plate and sill, as well as to all of the intermediate hoops. These boards may be of 

 hemlock, or poplar and of second or third rate quality, for their province is simply 

 to hold plastering lath, which in turn sujiports a coating of good cement. If after 

 this cement has hardened and dried thoroughly it is treated to a coat of gas tar 

 thickened with slate ground to flour, an enduring and perfectly impervious lining 

 will result, examples of which after 16 years in constant use may be cited in this 

 State. 



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