RURAL ENGINEERING. 485 



Fifty-eight acres were cleared uuder contract, tlie followiiif:; cuuaparisons be- 

 iiiR made : Twenty acres of swampy ground were cleared with a 40-horsei)ower 

 donkey engine at a total average cost of $398 per acre. Twenty acres with no 

 swamp were cleared by " a practical man wilh a good crew and teams " at a 

 cost of !f;>;>.S i)or acre. The total cost per acre of clearing seven acres of similar 

 land which had previously been slashed was $24(5, and of seven acres previously 

 cleared of brush by a forest fire $189. Four similar acres w^ere cleared by a 

 crew, stumi) puller, and team at a cost of $212 per acre. 



Two trials of the charpit system were unsuccessful, owing to heavy rainfall. 

 Two tests, made on two large stumps standing side by side to see whether, by 

 running a cable from each to a 7-ft. stump and tightening it by wedges, the 

 side tension would help in pulling the stump clear of the ground when blown 

 up. were unsuccessful. 



Stump burning to reclaim logged-ofE lands, Le R. W. Allison (Eiujin. Rec, 

 10 {191. 'f). No. .',, pp. .9J. 96. ftf). 1). — Methods and costs of clearing tracts of (ir 

 r.nd pine stumps for agriculture in the Pacific Northwest are given. The Imrn- 

 iug out of the I'oots by charpitting is said to be the most favored method. A 

 plant for this purpose is described, which consists of a gasoline engine, a 5-fire 

 stump burner, a cordwood saw, a power grubber, a geared horse stump puller, 

 and a power stump iiuller. 



Annual report of the state highway department {Ann. Rpt. t^tatc Ilifjluvdij 

 Dcpt. Ohio, 8 {1912). pp. 276, figs. 1,)6). — This includes the reports of the bu- 

 reaus of construction, maintenance and repair, and bridges, and of the state 

 testing laboratory. A number of plans and illustrations accompany these 

 reports. 



In a report on the road materials of Ohio, sedimentary rocks are said to 

 ri'edominate and are represented by the following varieties: Shale, sandstone, 

 limestone, dolomite (dolomitic or magnesian limestone), conglomerate, uuder- 

 clay. fii"e clay, chert or flint, coal, iron ore, clay, sand, and gravel. 



Additional rules and regulations governing state road work for year 1913 

 {State Ilifjhird!/ Con. Minn. Bui. 10 {1913), pp. 8, p/.s\ 6).— Detailed plans and 

 working data for plain and reinforced highway culverts are given. 



Standard culvert designs {Cement Era, 12 {19U), No. 10, pp. 51-53, 63, figs. 

 IS). — Standard plans, together with quantities of material and reinforcing, are 

 given for different sizes of circular concrete culverts as designed by the Iowa 

 Highway Commission. 



Some tests on a Diesel engine, W. S. Burns {Gas Engine, 16 {1914), ^o. 10, 

 pp. 615-621, figs. 11). — Tests on the effect of (1) variation of blast pressure and 

 <2) variation of .jacket water temperature upon tlie running of a Diesel engine 

 are described and the results reported graphically. 



It was found that at all loads too low a blast pressure pulverizes the oil im- 

 perfectly, causing late ignition and incomplete combustion with increase of 

 exhaust pressure and temperature above normal, while too high blast pressure 

 causes late but violent ignition attended again by incomplete combustion of the 

 oil. At all loads an increase of jacket water temjieraturo did not seem to 

 affect the point of ignition of the oil appreciably, but caused more rapid and 

 more complete combustion with increased efficiency. 



A rating chart for centrifugal pumps, L. J. Be^vdford {Engin. News, 72 

 {19l.'f). No. 8. pp. 3S2-384. figs. -{).— A grai)hical rating table is given to facili- 

 tate the selection of pumps when the si>eed. head, and capacity are given. 



The present status of mechanical cultivation in Europe, F. Ledeboeb 

 {Meded. Proefstat. Java-Suikerindus., 4 {1914), No. 25, pp. 491-520, pis. 23; 

 Arch. Snikcrindiis, Nedcrland. Indie, 22 {1914). No. 19, pp. 689-718, pis. 22).— 

 A largo number of mechanical cultivating machines, grouped uuder the two 



