EUKAL ENGINEERING. 593 



$1.26 with cut-back petroleum residue. When no oil was used the cost was 

 §;1.13. At the time of the last inspection all sections were in excellent condi- 

 tion with no important dfferences apparent between them. 



Oil-cement-concrete applications in New York City cost 89.33 cts. and 85.28 

 cts per sq. yd. using fluid residual petroleum, and $1.02 using cut-back petro- 

 leum residue, but the results are reported as being apparently less satsifactory 

 than those in Washington. The diAision line between each day's work was 

 evident, and the entire surface was rather rough and imeven. Bridge-floor 

 surfaces were also constructed of these materials at Ridgewood, N. J., and 

 when last inspected were found to be in good condition. The estimated cost 

 was 46.08 cts. per sq. yd. using fluid residual petroleum, and 41.47 cts. using 

 cut-back petroleum residue. 



Brief supplementary notes are given on the condition of roads constructed 

 in previous years at Youngstown, Ohio, Ithaca, N. Y., Newton, Mass., Independ- 

 ence, Garden City, Dodge City, Bucklin, and Ford, Kans., and at Bowling 

 Green, Ky. 



Bituminous dust preventives and road binders, P. Hubbard (U. S. Dept. 

 A(jr. Yearbook 1910, pp. 291-306). — The use of bitumens as dust preventives 

 and road binders is discussed, and the preparation, classification, selection, and 

 application of such materials ai"e described. The following conclusions are 

 drawn : 



" Bituminous road binders may be employed in the construction of earth and 

 gravel roads as well as macadam I'oads, but it is the latter type which, at the 

 present time, gives promise of the most .satisfactory results. The bituminous 

 macadam, if properly constructed, seems well adapted to withstand the com- 

 bined action of automobile and horse-drawn traflac. It is firm, resilient, and 

 water-proof, and is dustless in the same sense that an ordinary asphalt pave- 

 ment is dustless. Much depends upon the character of the bituminous binder 

 used, and it is most necessary that this binder be subject to examination and 

 certain specific tests, as in the case of cement, iron, steel, and other structural 

 material." 



[Drainage work in Ontario], W. H. Day (Ann. Rpt. Ontario Agr. Col. and 

 E.rj)t. Farm, 36 (1910), pp. 5.'t-T3, figs. 13). — The progress of the drainage cam- 

 paign in Ontario is discussed and a report given of the cement tile experiments 

 under way at the college. 



The view that underdrainage increases floods is considered unwarranted, and 

 instances are cited wherein tile drainage has materially lessened spring freshets 

 and soil erosion. 



In tests of making drainage tile by hand in 1909, the total cost, including 

 labor, of 1,000 hexagonal two-piece concrete 3-in. tile was found to be $10.64. 

 Trials in 1910 with another machine showed a cost for the sand and cement for 

 1.000 tile ranging from $3.35 for a 7 : 1 mixture and 3-in, tile to $11.29 for a 4 : 1 

 mixture and 6-in. tile. 



In 6 experiments to test the solubility of concrete tile, small samples were 

 submerged in distilled water and in well water for considerable periods. No 

 definite rate of solution could be established, but in all samples the rate ap- 

 peared to fall off in distilled water, slowly in most cases, but very rapidly in a 

 few, especially with clay tile. In well water the samples all behaved irregu- 

 larly at first, giving either large losses or large gains, and these losses or gains 

 subsequently fell off rapidly. 



Experiments with larger pieces kept in running water for 104 months showed 

 a much lower rate of solution, and, on the basis of the work, it is believed there 

 is no danger of concrete tile crumbling under ordinary conditions. The studies 

 are to be continued. 



