RURAl. ENGINEERING. 87 



The road materials of Wisconsin consist of gravel and field stone, limestone, 

 granite and trap rock, sandstone, and quartzite. There is great variation in the 

 quality of these materials. Some limestones of the State are absolutely unfit 

 for use on the roads, others can be used only with very careful treatment in 

 construction, but most of them make a satisfactory road material. The granites 

 and trap rocks also vary greatly in character, but all are good. The most variable 

 road material in the State, and one of the most valuable, is the gravel. This 

 material is so extremely diverse in character that the method of treatment 

 adapted to material from one end of a single pit may not be at all suitable for 

 material from the other end. The limestones furnish the greatest amount of 

 crushed stone for road purposes in the State and are the only type of road mate- 

 rial considered in detail in this report. Tests of road material as conducted by 

 the Office of Public Roads of this Department are also described. 



Gravel aggregate for concrete, W. K. Hatt {Municipal Engin., 49 (1915), 

 No. 1, pp. 2-S, figs. 10). — Tests to ascertain the relative strength of concrete 

 of an arbitrary 1:2:4 proportion, when the line of division between the fine 

 and coarse aggregates is the J-in. sieve and when it is the ^-in. sieve, are reported. 

 It is concluded from the results that for the aggregates tested and the assumed 

 proportion the resulting concrete Is as strong, if not stronger, when the line of 

 division is on the ^-in. screen. 



Investigation of the effects of alkali on concrete drain tile near Lake 

 Park, Iowa, C. E. Sims and G. P. Dieckman {Concrete-Cement Age, 6 {1915), 

 No. 6, pp. 278-281). — An investigation of the failure of concrete drain tile in 

 soils containing appreciable quantities of calcium and magnesium sulphates led 

 to the conclusion that the use of good materials in proper proportions to make 

 dense concrete, compacting the mixture well, and aging the product for a month 

 at a temperature above freezing will protect the concrete tile against alkali. 

 " Knowing that concrete becomes more dense with age, it seems that if the 

 absorption is less than 5 per cent in concrete thirty days old it ought to be alkali 

 proof and suitable for any service." 



Report committee on electricity on the farm, Western States ( [Nat. Elect. 

 Light Assoc, 1912-13], Manuscript, pp. 14). — This report presents the sub- 

 stance of answers to inquiries sent out by the National Electric Light Associa- 

 tion to different power companies in the Western States to obtain information 

 as to the farm use of electricity. 



The answers indicate that the use of electricity for agricultural purposes in 

 the West is most extensive in the States of Washington, Oregon, California, and 

 (Colorado, while interest is manifested in several other States. " The most inter- 

 esting thing brought out was the great difference in the method of charging 

 for the power and the amount of the charge. . . . The use of electricity on 

 the farm is necessarily a seasonal use, the greatest demand being for pumping 

 for irrigation. Depending on the locality and on the crop to be irrigated, the 

 irrigating season under normal conditions is from April to October, inclusive. A 

 dry year, such as has just been experienced in California, will make the season 

 longer. ... It is very apparent, therefore, that it is to the power company's 

 advantage to have the consumer make his installation as small as possible and 

 operate as many hours per day as possible." 



Copies of agricultural rate schedules from various companies operating in the 

 different States are appended. 



Priming a centrifugal pump, E. M. Ivens {Poicer, 41 {1915), No. 26, pp. 

 880-882, figs. 8). — Several methods of priming centrifugal pumps and of over- 

 coming priming troubles are described with illustrations. 



15419°— No. 1—16 7 



