888 



EXPERIMENT STATION RECORD. 



I Vol. »5 



reported. The number of 0.5-lb. sticks of dynamite useil per stump varied from 

 1 to 9.5, averaging 3, and the cost per stump varied from 20 cts. to $1.68, 

 averaging 59 cts. 



Brief instructions on handling the explosive are also included. 



British standard nomenclature of tars, pitches, bitumens, and asphalts, 

 when used for road purposes, and British standard specifications for tar and 

 pitch for road purposes, L. S. Robertson {Engin. Standards Committee Rpt. 

 76 {1916), pp. 16). — These specifications and definitions were approved by the 

 British Engineering Standards Committee, supported by five British national 

 engineering societies. 



Motor truck lessens cost of maintaining gravel roads in Alabama, T. H. 

 Edwards {Engin. Rec, 74 {1916), No. 3, pp. 73, 74, figs. 6).— Working data for 

 650 miles of road are reported which indicate that from 16 to 20 mules may 

 be replaced by a motor truck for pulling a scarifier, and complete scraping 

 after every rain is made possible, the truck drawing three road machinas cov- 

 ering 30 miles a day. The cost of hauling gravel was reduced from 30 to 40 

 cts. to from 7 to 11 cts. per yard-mile and included spreading on the road in 

 addition. 



Public road mileage and revenues in the Middle Atlantic States, 1914 

 {U. S. Dept. Agr. Bui. 386 {1916), pp. 27, fig. i).— This bulletin contains "a 

 compilation showing mileage of improved and unimproved roads; sources and 

 amounts of road revenues ; bonds issued and outstanding ; and a description of 

 the systems of road administration and fiscal management, and of other factors 

 affecting road improvement in each State." 



Neva- tests of bolted joints in timber framing, H. D. Dewell {Engin. News. 

 76 {1916), No. 3, pp. 111-115, figs. 7).— Tests of 24 bolted joints, 10 all-timber 

 lagscrewed joints, 4 joints in which a steel plate was lagged to timbers with 

 J-in. and J-in. lagscrews, and 13 tests made to determine the bearing resistance 

 of a round bolt against the ends and across the fibers of Douglas fir are reported. 

 " The author believes that the following conclusions and recommendations for 

 working data, made from a study of the tests, are justifiable and reasonably 

 conservative : 



" For bolts with driving fit in the timbers the strength of the joint is prac- 

 tically independent of the thickness of the side pieces, when this thickness 

 exceeds the limiting value 't.' While the ultimate strength of the joints whose 

 bolts have cross-bearing in the main timber is far below that of the all-end- 

 bearing joints, the stiffness of such joints up to the break in the curve is 

 practically the same. 



"The same loads for bolts in joints like those described, having all end 

 bearing, may be taken as per [the following] : 



" Working strength of one bolt in timber joint (bolt in double shear) for joints 

 similar to test joints, with bolts hearing against the end of the grain. 



"These values correspond fairly well to one-half the loads for ^-in. slip. 

 These working loads are consistent with the results of tests on nailed joints. 



