I 



1016] EURAL ENGINEERING. 387 



When apparently soiind tile were so placed for four months as to be exposed 

 to the action of the elements, to the action of water in a river bed to determine 

 rhe effect a large amount of water coming in contact with the surface, and to 

 the action of sewage by placing them in the discharge waters at a sewer outlet, 

 no effect of the exposures was observed. When porous tile were placed in soil 

 and water caused to percolate through their walls no disintegration was 

 observed, but analyses of the water showed that some of the cement had been 

 dissolved. 



To show the effect of soil water upon the cement in concr(^to tile porous cups 

 were prepared from pure quartz sand and cement and different solutions caused 

 to pass through their structure. The results obtained are taken to indicate that 

 " any solution percolating through concrete tile will dissolve some of the 

 cement ; in other words, some of the material which is necessary to maintain 

 the tile structure intact, and point conclusively to the necessity for an im- 

 pervious tile wall structure. Experiments also showed that solutions would 

 percolate through incompletely hardened tile much more rapidly than through 

 tile that had been properly and completely hardened ; so the action of solu- 

 tions upon partially hardened concrete tile is greater than upon those which 

 have been pi'operly hardened. . . . Conclusions reached from these preliminary 

 experiments seem to point to the following as the most important factors for 

 consideration in manufacturing concrete tile to fulfill desired requirements : 



"(1) A Portland cement, meeting the requirements of the standard specifica- 

 tions for Portland cement of the American Society for Testing Materials, as 

 revised to date. (2) Clean and preferably siliceous sand, graded in size from 

 the finer particles to those which will just pass a i-in. mesh screen, for all tile 

 10 in. and less in diameter. (3) Proper and accurate proportioning of the 

 cement and sand. The method- of measuring materials should be one which 

 will insure separate and uniform proportions of each of the materials at all 

 times. (4) Thorough mixing of materials, preferably by a power-operated 

 batch mixer, and continuing for at least one minute after all materials, in- 

 cluding water, are in the mixer. (5) Using a machine that accomplishes thor- 

 ough packing of materials at proper consistency. (6) All other conditions of 

 manufacture having been as outlined, hardening in a properly equipped and 

 operatetl steam room will produce tile of the highest grade. When, however, 

 hardening by water vapor is not possible, tile must be kept constantly Vv-et on 

 the surface by sprinkling with water for not less than seven days under favor- 

 able weather conditions, and longer during cold weather." 



Details of these factors are discussed together with samples of concrete tile 

 received which had failed. 



Ground water in the Hartford, Stam^ford, Salisbury, Willimantic, and 

 Saybrook areas, Connecticut, H. E. Gregory and A. J. Ellis (f7. S. Gcol. Sur- 

 vey, Water-supply Paper 37// (1916), pp. 150, pis. 13, figs. iO).— This is a report 

 on the origin, occurrence, distribution, and quality of the ground waters of five 

 typical areas in Connecticut, with reference to their use for irrigation, farm 

 domestic water supplies, and municipal water supplies. 



Surface water supply of Ohio River basin, 1914 (U. S. Geol. Survey, Water- 

 Supply Paper 3S3 (1916), pp. 125-\-XXXII, pis. 2).— This report, prepared in 

 cooperation with the States of West Virginia and Illinois, presents the results 

 of measurements of flow made on streams in the Ohio River basin during 1914. 



The underground and surface water supplies of Wisconsin, S. Weidman 



and A. R. Schultz (Wis. Geol. and Nat. Hist. Survey Bui. 35 (1915), Econ. Ser. 



11, pp. XXII-\-664. pis. 5, figs. 12). — This report, prepared in cooperation with 



the U. S. Geological Survey, deals with the general conditions affecting Wis- 



56493"— 16 1 



