19181 RURAL ENGINEERING. 87 



with some form of surfacing. The mileage of hard-surfaced roads is increasing 

 at the rate of about 15,000 miles per annum. During 1916 the States having 

 State highway departments surfaced about 7,000 miles under State supervision 

 and also improved an additional 9,000 miles by grading or otherwise. Thus, of 

 the really constructive work of permanent improvement in the United States 

 last year, about one-half was more or less directly under competent State super- 

 vision. In addition to this work of construction the several State highway 

 departments also supervised the maintenance of 75,811 miles of main and trunk- 

 line highways." 



Tabular data are included on expenditures during 1916 by or under the super- 

 vision of State highway departments, on road mileage, and on cash road and 

 bridge expenditures for the years 1904, 1914, and 1916. 



Third biennial report of the Wisconsin Highway Commission 1914—15 

 (Wis. Highway Com. Bien. Rpt., 3 {1914-15), pp. 329, figs. i72).— This report 

 covers State aid road and bridge construction in Wisconsin for the calendar 

 years 1914 aud 1915, and Includes a preliminary report of similar operations in 

 the calendar year 1916. 



Standard forms for specifications, tests, reports, and methods of sampling 

 for road materials ({7. S. Dept. Agr. Bui. 555 {1911), pp. 56, fig. 1). — These 

 standard forms were recommended by the first conference of State highway 

 testing engineers and chemists at Washington, D. C, from February 12 to 17, 

 1917. 



Dust prevention by the use of palliatives, H. B. Shattuck {Ann. Rpt. 

 Penn. State Col., 1915, pp. 153-162). — This is a brief description of the use of 

 fresh water, sea water, calcium chlorid, waste sulphite liquor, vegetable and 

 animal oils, road oils, emulsions, and tar as dust preventives on roads. 



" Earth roads will usually best respond to treatment with water, calcium 

 chlorid, and light oils. Gravel and macadamized roads may be treated with 

 these or with asphalts, emulsions of oils, and tars. Very sandy roads will be 

 Improved if a suitable amount of clay is first mixed with the sand and the 

 whole consolidated before the application of a dust preventive. In like man- 

 ner a very clayey road should be given a suitable admixture of sand to pro- 

 duce a better stability before the surface treatment." 



Concrete in the country {Chicago: Portland Cement Assoc., 1916, 13. ed., pp. 

 112, figs. 134). — This bulletin describes and illustrates the construction of a 

 large number of farm structures, using concrete as a building material. 



Tests showing' the effect of using dry and wet coal as fired in a low-pres- 

 sure steam-heating boiler, J. J. Light {Ann. Rpt. Penn. State Col. 1915, pp. 

 148-152). — Tests on the efficiency of a house-heating plant when fired with 

 coal made wet and with coal as usually found in residence cellars, which can 

 be considered practically dry, are reported. 



It was concluded that " the common inference among coal consumers that 

 an addition of water to the coal as fired is beneficial to the operation of the 

 furnace seems false. . . . One lb. of combustible evapoi'ates more when the 

 coal is fired dry or as is ordinarily found in cellars of residences than when it 

 is purposely moistened. The efficiency of the furnace throughout the tests 

 shows that wet coal tends to decrease rather than increase operating economy." 



Effect of velocity and humidity of air on heat transmission through build- 

 ing materials, J. A. Moyek, J. P. Calderwood, and M. P. Helm an {Ann Rpt. 

 Penn. State Col. 1915, pp. 55-62, pis. 6). — Experiments on heat transmission 

 through glass, common red brick, and diatomite insulating brick are reported. 



" These data show that the transmission through glass and red brick are 

 Increased very materially with increase in humidity. Thus for glass the unit 



