722 



SCIENCE. 



[N. S. Vol. XXI. No. 541. 



of Agriculture.' He showed that while 

 chemical analysis may show that two soils 

 are equally rich in plant food, yet on ac- 

 count of unfavorable water conditions, one 

 of them may be quite unproductive, and 

 the different portions of even the same 

 field may vary in their production on ac- 

 count of differences in the water content of 

 the soil. The supply of water and the con- 

 trol or regulation of its quantity in soils of 

 different classes under varying climatic 

 conditions for the production of crops of a 

 first-class character present an important 

 field which now occupies the attention of 

 th,e irrigation and drainage investigations. 

 The objects of this work are to ascertain 

 the best methods and provoke their use in 

 applying water to soils where it is deficient, 

 conserving and regulating its quantity, re- 

 moving surplus from saturated soils and 

 reclaiming and protecting lands from over- 

 flow, all of which invokes a variety of en- 

 gineering practise. The soil water neces- 

 sary for the growth of plants is held about 

 soil drains in films and is removed from the 

 soil by capillarity, plant absorption and 

 surface evaporation only. Irrigation must 

 supply this amount when deficient, and 

 any surplus must be removed by drainage. 

 The water-holding capacity of different 

 soils is an important subject for investiga- 

 tion. The part of the engineer is to pro- 

 vide means for supplying, regulating and 

 controlling the soil water to meet the needs 

 of the various kinds of soils encountered 

 and plants grown therein, and includes a 

 study of the movements of water, both by 

 capillarity and by gravity. 



Henry S. Jacoby, professor of bridge 

 engineering, Cornell University, Ithaca, 

 N. Y., presented 'Some Notes on Eein- 

 forced Concrete Arches,' giving the results 

 of his study and investigations during the 

 past year and supplementing his previous 

 papers. 



E. J. MeCaustland, assistant professor 



in civil engineering, Cornell University, 

 Ithaca, N. Y., next presented a paper on 

 'Tests of Eeinforced Concrete Beams,' in 

 which he presented the data and conclu- 

 sions obtained from the tests to failure of 

 twenty-three beams of concrete, reinforced 

 by plain and various forms of patented 

 bars of steel. They were 6 by 8 inches in 

 size and 6 feet long. Plain square steel 

 rods were used, varying in sizes from f to 

 f inch and placed either or 2 inches 

 from the lower face of the beam. The 

 beams were made of a very lean concrete 

 (1 cement, 2.5 sand and 9 broken lime- 

 stone), so that in all cases the steel rein- 

 forcing bars developed full strength of the 

 concrete before reaching the elastic limit. 

 Deflections were measured, and also the 

 extensions of the lower fibers. A careful 

 watch was kept to determine the appear- 

 ance of fine cracks. The loads were re- 

 leased after each reading so as to measure 

 the set. Tests of the beams with plain 

 square bars showed poor adhesion and the 

 early development of fine cracks, so that 

 the smallest percentage of reinforcement 

 seemed sufficient. The beams having rein- 

 forcement 1| inches from the lower face 

 showed greatest strength. In the second 

 series sets of beams were laid up with rein- 

 forcements of Ransome bars, Johnson cor- 

 rugated bars, Kahn bars, corrugated bars 

 with iron stirrups, Thatcher bars, and two 

 beams with plain bars for comparison. The 

 ratio of reinforcement was made about 0.58 

 per cent, and the center of the steel bars 

 was placed 1^ inches from the lower face 

 of the beams. The extensibility of the re- 

 inforced concrete in these tests was one in 

 1,621, while that of the plain concrete was 

 one in 11,000. The results show the su- 

 periority of the corrugated bars under 

 ordinary conditions. They also draw sharp 

 attention to an interior weakness in a rein- 

 forcement having dia£:onal wings rigidly 

 attached. The tests show the folly of at- 



