292 EXPERIMENT STATION EECORD. [Vol.35 



and as the percentage of hydrate of lime was increased the mass became more 

 sticky and did not flow so readily. By far the most important observation made 

 was that the addition of hydrate of lime did prevent segregation, and so much 

 so as to make this the biggest gain that can be gotten from the use of hydrate 

 of lime." 



Experiments on wire rope, M. Rudeloff (Mitt. K. Materlalprilfungsamt 

 Berlin-Lichterfelde West, 33 (.1915), No. 5-//, pp. 198-209, figs. iO).— Experi- 

 ments on the strength of four wire ropes gave inconclusive results. Experi- 

 ments on the durability of three wire ropes containing, respectively, 294, 210, 

 and 294 wires of 0.7, 0.68, and 0.59 sq. mm. cross section and having respective 

 total wire cross sections of 113.1, 76.3, and 80.4 sq. mm. and total diameters of 

 20, 17, and 17 mm., are also reported. The second rope was found to be the 

 most resistant and the third the least resistant. 



Consideration on hauling by animal and mechanical power, F. Achilles 

 (Wchnschr. Brau., 32 (1915), Kos. 7, pp. 49-53, figs. 6; 8, pp. 62-64, figs. 2; 9, 

 pp. 88-90, figs. 2). — The results of an investigation into the factors affecting the 

 efficiency and economy of hauling loads by animal power and by motor truck 

 are reported in both tabular and graphic form and analyzed to determine the 

 limits of the efficiency and economy of the two types of power under different 

 conditions. 



A final graphic comparison of the cost of hauling by the two kinds of power 

 is made which is based on the cost per ton kilometer and the daily accom- 

 plishment in ton kilometers. This comparison shows that up to a daily ac- 

 complishment of about 200-ton kilometers animal power hauling one wagon 

 for 100-ton kilometers per day and two wagons for from 100 to about 200 ton 

 kilometers per day is more economical than one motor truck of 2 tons capacity. 

 With a daily accomplishment of from 200 to 700 ton kilometers it is shown 

 that the motor trtuck alone in varying capacities or a train of motor trucks is 

 more economical than a train of from three to eight wagons drawn by animal 

 power. 



An economic study of the farm tractor in the com belt, A. P. Yerkes and 

 L. M. Church (U. S. Dept. Agr., Farmers' Bui. 719 (1916), pp. 24, fig. i).— This 

 bulletin reports and discusses data from selected reports from over 200 tractor 

 owners in Illinois whose farms are typical of corn-belt conditions, the data be- 

 ing considered correct for conditions existing in the corn belt in the spring 

 of 1916. 



The principal points brought out by the experience of these owners are sum- 

 marized as follows : 



" The chief advantages of the tractor for farm work, in the opinion of the op- 

 erators, are (1) its ability to do the heavy work and do it rapidly, thus covering 

 the desired acreage within the proper season; (2) the saving of man labor, and 

 the consequent doing away with some hired help; and (3) the ability to plow 

 to a good depth, especially in hot weather. The chief disadvantages are diffi- 

 culties of efficient operation and the packing of the soil when damp. 



" The purchase of a tractor seldom lowers the actual cost of operating a farm, 

 and its purchase must usually be justified by increased returns. 



" One of the most important points in connection with the purchase of a 

 tractor is to obtain one of suitable size for the farm on which it is to be used. 

 In this connection experienced tractor owners in Illinois make the following 

 recommendations : 



" For farms of 200 crop acres or less, the 3-plow tractor ; for farms of from 201 

 to 450 crop acres, the 4-plow tractor, with the 3-plow outfit second choice; for 

 farms of from 451 to 750 crop acres, the 4-plow tractor, with the 5- and 8-plow 

 outfits tied for second choice ; a farm of 140 acres is the smallest upon which the 



