RUKAL ENGINEERING. 387 



western United States and from the results of 50 years' reported use of the 

 same method in India the author recommends the painting of concrete structures 

 with a mixture of 2 parts boiled and 1 part raw linseed oil as a protection 

 against alkali and other destructive agencies. Coincident with oil painting he 

 recommends the use of highly silicious cements, and where work is constantly 

 under water, of slag cement, as well as the employment of all precautions to 

 insure a dense mixture. It is suggested that the oil coating, as the primary 

 reliance for protection, be applied after the concrete is 6 mouths old and be 

 renewed at least every 5 years. 



Tests of grouting' gravel in river beds, H. H. Cartwright {Engin. Netos, 

 69 (1913), Mo. 19, pp. 919-9SJt, figs. iO).— This article describes extensive experi- 

 ments with the process of injecting cement into sand and gravel to form con- 

 ci"ete in place, conducted for the purpose of ascertaining the possibility of its 

 use in river beds composed of sand and gravel deposits. 



Both poor and good concrete were obtained in the experiments, varying from 

 a cemented gravel very poorly bonded to a very hard, perfectly bonded concrete. 

 In spite of the fact that there were noticeable defects in aU the concrete this 

 process is concluded to be a feas-ble method for forming hai-d foundation strata 

 on which to found masonry structures, and should also prove of value in solidi- 

 fying and protecting stream beds against scouring and washing. 



Bending stren^h of yellow-pine timber, J, J. Morgan {Engin. Rec, 67 

 (1913), No. 22, pp. COS, 609, figs. S).— Tables of safe loads for beams and 

 girders of standard dimensions are given which provide for the defect in stand- 

 ard tables due to the fact that the standard sizes of timber are from i to ^ in. 

 less in both depth and thickness than called for in their normal sizes. 



Roads and road materials of Florida, E. H. Sellards, H. Gunter, and N. H. 

 Cox (Fla. Geol. Survey Bui. 2, 1911, pp. 31, pis. 4).— This bulletin reports by 

 counties on the road materials in Florida and on the progress of road building 

 operations in that State up until the close of the year 1910. The road building 

 materials classified according to their chemical composition are given as follows : 

 Flint, chert, sandstone, infusorial earth, shell, crystallized and oolitic limestone, 

 marl, clay, shale, muck, peat, lignite, bog iron ore, and pebble and rock 

 phosphate. 



Under the present system the county is the unit of road management and the 

 county commissioners are in charge of road construction and responsible for 

 the expenditure of road funds. Seven of the counties employ road engineers, 8 

 counties have issued bonds for road improvement, and several of the counties 

 use county convicts for work on the roads. 



A summary of the report from the several counties sLovrs that at the close 

 of 1910 the total number of miles of improved roads in Florida, exclusive of 

 graded dirt roads, was 2,070. Of this number 611.3 miles were surfaced with 

 marl or crushed stone ; 146.1 miles with shell ; 22.5 miles with gravel ; 8.5 miles 

 with brick ; 0.4 mile with asphalt ; and 5.2 miles with cement. Approximately 

 1,000 miles were surfaced with sand clay, and 277 miles were temporarily im- 

 proved by the use of pine straw. The total expenditure on public roads in the 

 44 counties which reported was $1,080,949. 



Specifications for street roadway pavements, S. Whinery (New York and 

 London, 1913, 2. ed., rev. and cnl., pp. X-\-160, fig. 1). — This book contains gen- 

 eral specifications, embodying the latest approved practice for the proper con- 

 struction of pavements of the several standard kinds. In addition is given a 

 set of instructions for inspectors in charge of such construction. 



Comparative statistics on cost of road construction (Engin. and Contract., 

 39 (1913), No. 20, pp. 5.'i'f-5'i8).—A large amount of data collected by the con- 



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