1916] RUKAL ENGINEERING. 789 



Blasting ditches, H. E. Muedock {Montana Sta. Circ. 55 (1916), pp. 1S5-VJ2, 

 figs. 7). — This circular gives rlata secured on blasting open drainage ditclies ou 

 tlie station farm at IJozenian, Mont. The soil is very gravelly and contains 

 many large rocks, making digging difficult and expensive. 



" In the blasted ditch two sticks of CO per cent dynamite were placed in holes 

 22 in. apart. This distance was determined by experimenting to be the most 

 desirable for the soil conditions. When the holes were spaced 22 in. or less 

 ordinarily only one charge was needed for a primer, as the others would be 

 exploded by concussion. When spaced farther apart some holes would mis-fire, 

 When .spaced less than 22 in. there was a waste of dynamite, as there was no 

 additional benefit to the ditch. The holes were driven by tool-steel bars 2..5 ft. 

 long. ... In the work done in 1914 the holes were spaced 20 in. apart and 

 electric caps and a blasting machine were used." 



" A comparison of three lengths of ditch constructed in 1915 is as follows : 

 Fourteen rods of hand-dug ditch cost $3.35 per rod, 17 rods of blasted ditch $3.10 

 per rod, and 39.2 rods of blasted ditch ,$2.36 per rod. 



First biennial report of the state highway commission [of Idaho] for the 

 period ending December 31, 1914 {Bien. Rpt. State Highivay Coin. Idaho, 

 1 (191^). pp. 81, pis. 25, fig. 1). — The work and expenditures on roads in Idaho 

 for the biennium ended December 31, 1914, are reported. 



Annual report of the highways division [of Nova Scotia] for the year 

 ended September 30, 1915, H. Donkin (Ann. Rpt. Highways Div. Nova Scotia, 

 1915, pp. 97, pis. 9, fig. 1). — Data on the work and expenditures on roads in 

 Nova Scotia for the year ended September 30, 1915, are presented in detail. 



Constitution and statutes of the State of Oregon relating to roads, high- 

 ways, bridges, and ferries, compiled by B. W. Olcott (Salem, Or eg.: State 

 Print. Dcpt., 1915, pp. 221). — The text of the legislation is given. 



A handy road chart, N. G. Near (Engin. and Contract., Jt6 (1916), No. 1, 

 p. 21 fig. 1). — A chart for the use of road builders in determining the number 

 of square yards in any road up to nearly 2 miles in length and in any width up 

 to 1,000 ft. is given. 



Minimum tire widths for good roads, H. L. Hock (Cornell Civ. Engin., 24 

 (1916), No. 9, pp. 469-475, figs. 3). — In a brief review of the laws and technical 

 data on the subject the author recommends " the adoption of a law which 

 shall permit a maximum load of 250 lbs. per inch width per tire, if the tire is 

 of wood, metal, or other hard material ; and 300 lbs. per inch width per tire if 

 of rubber or other resilient material." 



Some comparative tests of wire-cut-lug and repressed paving brick, W. A. 

 Goss (Engin. and Contract., Jf6 (1916), No. 1, pp. 8-11, figs. 2). — Abrasion, 

 standard abrasion, standard absorption, specific gravity, cross bending, com- 

 pression, shear and impact tests conducted at the University of Wisconsin on 

 wire-cut-lug and repressed paving brick, are reported. 



" The determinations arrived at as a result of these tests are that the wire- 

 cut-lug bricks have better abrasive and wearing qualities, greater density, 

 greater crushing strength; the repressed brick have greater weight per unit 

 volume, greater toughness. ... In addition the wire-cut-lug brick are of more 

 uniform quality than the repressed. 



" The tests show that both types of the brick tested were of good quality for 

 paving purposes. Either brick is plenty strong and tough enough for use In a 

 pavement. The difiierence in wearing qualities and in uniformity are the most 

 important determinations of these tests, and in these characteristics the wire- 

 cut-lug brick have shown superiority. This difference is not marked, however, 

 and it would be necessary to test out brick from other plants before one could 

 state just what degree of difference exists." 



