RURAL ENGINEERING. 293 



The sifters were thoroughly tested in connection with the mill by grinding 

 and sifting rye containing 13.89 per cent moisture and weighing 70.9 kg. per hec- 

 toliter. Four sifters were used in the following order: A No. 20 with 20 wires 

 per 26 mm., 2 No. 8 with 34 wires, and a No. 9 with 38.5 wires. This test was 

 run under 3 different adjustments and speeds, yielding flour, coarse meal, and 

 bran in vai-ying quantities. The results indicate that the most satisfactory 

 speed for this purpose is between 5G0 and 570 r. p. m. With the same arrange- 

 ment 25 kg. of hulled rye underwent a similar process for 1 hour and 14 min- 

 utes. Within 17 minutes the yield was as in the first 3 tests. After 48 min- 

 utes more. 11.68 kg. of fine medium white flour and 4.50 kg. of fine black flour 

 had been yielded. At this point the following arrangement of sifters was 

 substituted : A No. 18 sieve, with 18 wires per 26 mm., a No. 8, a No. 9, and a 

 No. 5, which contained 1 wire per mm. Within 7 minutes the remainder of the 

 rye was reduced to 1.24 kg. of fine flour, 2.13 kg. of coarse flour, 4.48 kg. of fine 

 bran, and 0.145 kg. of coarse bran. The maximum horsepower required in this 

 test was 3.3 and the average 1.8, and the average power consumption was 2.2 

 h. p. hours. 



Diagrammatic plans of the mill are given with curves of the test results. 



The effect of saturation on the strength of concrete, J. L. Van Ornum 

 (Proc. Amer. Soc. Civ. Engin., 39 {1913), No. 6, pp. 1229-1236, fig. Jf).— Results 

 of several series of tests on concrete specimens, both plain and reinforced, indi- 

 cate a rapid decrease in strength for the first 2 days of submergence and a sys- 

 tematic increase in strength thereafter. Specimens stored tor 38 days in air un- 

 derwent a rapid decrease in strength when placed in water for 2 days or less 

 but increased in strength after saturation was complete. 



Test of pressure of wet concrete, E. B. Germain (Engin. News, 70 (1913), 

 No. 7, pp. 294, 295, figs. 2). — A recent test of the pressure of wet concrete to 

 determine the proper figures to be used in the design of forms was made on 

 small area columns where a high head could be produced in a short time. The 

 apparatus used consisted of an ordinary hot-water bag filled with water, a test 

 tube containing mercury inside the bag, and a hollow glass column running from 

 below the surface of the mercury in the tube through a rubber stopper in the 

 neck of the hot water bottle. Six of these bags were placed in each of 2 

 columns, 20 in. square and about 20 ft. high, and the mercury levels read on 

 each after the column was filled, the difference in levels of the mercury in the 

 test tube and in the column giving the pressure in inches of mercury. 



Using a mixture of 1: 1* : 3, the pressure per square inch wcs 460 lbs. with a 

 head of 3.08 ft., 900 lbs. for 6.08 ft., 1,330 lbs. for 9.08 ft., 1,710 lbs. for 12.08 

 ft., and 2,110 lbs. for 15.08 ft. With a mixture of 1 : 1 : 1 the pressure was 407 

 lbs. for 2.75 ft., and 840, 1,280, 1.700, 2,080, and 2,450 lbs., respectively, for 

 heads, of 5.75, 8.75, 11.75, 14.75, and 17.75 ft. 



Since the first concrete put in begins to set before the last concrete is poured, 

 the pressures in the lower part of the columns do not show quite full liquid 

 pressure. 



Tests of reinforced concrete building's under load, A. N. Talbot and W. A. 

 Slater (Univ. III. Engin. Expt. Sta. Bui. 6/,, 1913, pp. 101,. figs. 75).— This bulle- 

 tin records the results of field tests made on 3 reinforced concrete floor sys- 

 tems, 2 of the beam and girder type and 1 of the flat slab type. In addition is 

 included a discussion of the method of testing, the use of the instruments, 

 methods of observation, precautions to be taken, accuracy of results, and 

 methods of loading. 



No specific conclusions are drawn because of the wide scope of the tests. 



Constructing- a silo roof of concrete (Building Age, 35 (1913), No. 8, pp. 

 S67, 368, figs. 4)- — The construction of a conical reinforced concrete silo roof is 



