688 EXPERIMENT STATION EECORD. 



of this resistance is sliown by tlie time in seconds required for 3 complete revo- 

 lutions of the cylinder. The temperature of the oil on the cylinders is regulated 

 by means of water pipes. 



Tests of several road oils show a wide range of adhesive power. A wide range 

 is also shown in the ratio of the float and viscosity tests to the adhesive tests, as 

 in the case of 2 oils having about the same viscosity yet one being 5 times as 

 adhesive as the other. 



An oil of veiT slight stick property was tested to determine if it could be 

 raised to the class of very sticky oil by the use of resin. On the addition of 10 

 per cent of resin the stickiness was increased about 3 times and with 25 per cent 

 of resin added the stickiness was increased about 6 times. The results of sev- 

 eral other adhesion tests of oils are given in tabular form. 



It is concluded that the adhesion test is a valuable addition to the testing of 

 road oil in that it gives new information in regard to one of the most important 

 properties of oil. 



Typical specifications for the fabrication and erection of steel highway- 

 bridges (U. 8. Dept. Agr., Office PiiJ). Roads Circ. 100, pp. 25).— This circular 

 has been prepared with the purpose of furnishing a suitable guide for local 

 highway officials in fixing requirements to which bridge structures must con- 

 form. The specifications deal in particular with loads, proportions and unit 

 stresses, floor system, details of design and construction, workmanship, mate- 

 rials, painting, concrete masonry, inspection and testing, and erection. 



Power farming, R. Olney (Laporte, Intl., 1913, pp. 56, pis. 9, figs. 42).— This 

 pamphlet gives suggestions for the selection and purchasing of mechanical power 

 for the farm, and outlines in detail the methods of utilizing such power for draft 

 and belt work. 



The roller or packer, H. B. Bonebright (Montana Sta. Circ. 21, pp. 27-32, 

 figg_ 6).— The construction of 2 types of cement corrugated rollers is described, 

 the first made with wheels of cement with bare faces and the second made with 

 cement wheels having steel faces. In the second type the hubs are placed in 

 position and the space between the rim and the hub filled with a wet mixture of 

 1 : 3 cement mortar. After curing the roller may be assembled, the molds being 

 left on the wheels and forming a steel covering for them. 



In the first type a wheel of wet wood is constructed, 4 in. thick and 19 in. in 

 diameter from edge to edge with the rim in the shape of the letter V and the 

 angle of the edge 90°. A wooden frame of 4 in. boards is then built around this 

 circular form, and with this a concrete form, 4 in. thick and 27 in. square is 

 made in 3 sections by filling m with a wet 1:2 mortar. By placing a hub in the 

 center of this cement mold and filling the space between hub and mold with 

 cement mixture the wheels are easUy cast. For reenforcement a few rings 

 about 14 in. in diameter of barbed or baling wire are recommended. It is sug- 

 gested that the hubs be made of gas pipe cut 4 in. long. For sections of rollers 

 not over 4 ft. long, li in. pipe should be used which fits over a 1^ in. shaft, and 

 for sections longer than 4 ft. 2 in., pipe should be used which fits over a lil in. 

 shaft. Two spikes are inserted in opposite sides of the hubs through holes 

 drilled for the purpose to prevent movement of the hub in the cement. The 

 shafting should be cold rolled steel. For frames 4 by 6 in. hard or soft pine 

 is recommended. 



A portable grain-drying machine, F. Holtzermann (Deut. Landw. Presse, 

 40 (1913), No. 46, pp. 554, 555, figs. 6).— A novel grain-drying machine, which 

 it is claimed has proved satisfactory in Russia, is described. 



In the operation of this machine the grain is deposited in a hopper from which 

 it passes to a circular plate inclosed in a sheet iron chamber and so perforated 

 as to allow the passage of hot air, but not the grain. The grain falls on the 



