RURAL ENGINEERING. 289 



"(e) Cost <il" ■•iiiiilyiiii,'' tlic walcr per arn> ; All;iir:i. $1.2.">: coni. HT> ds. ; and 

 sweet potatoes, (!4 cts. 



"(d) Thf yield per acre • Alfalfa. 2..".;> tons; corn, ."tl.!* I)U. ; and swecl potatoes, 

 10.000 lbs. 



"(e) The value of the cro]) ])er acre: Alfalfa, if85.08 ; wheat, .$18.00; corn 

 (includin.ij the stover), .$:!r).L'7 ; and s\v(>et potatoes. .$170." 



Public roads: Mileage and expenditures in 1904 (('. S. Dcpt. A(jr., O/jicc 

 J'lih. Ilniids Circs. .H). pji. .> : .'ill, pp. i: J/. /(/*. ,? .• .).>. ]ip. .> : .'i.i. pp. S; J/Ji, pp. Jf ; Jf5, 

 I'll- 'i ■' 'I'i- I'll- -^ ■' 'i^- Pit- 'i : '/•''• /'/'• .-.' ■'>'>- Vl>- - : '>l Pl>- 2; ')2, pp. 2). — Thes« 

 are a series of le.-iflets issued by the Ollice of Public Roads, U. S. Depart- 

 ment of A.t;riculture, in which road statistics are j^iven by States. The iiresent 

 luunbers include the States of Alabama, Arizona. Arkansas, Iowa, Maine. Mary- 

 land, New Hampshire, New Mexico, North Carolina, Oregon, Tennessee, Vir- 

 ginia, and Washington. For each of these States statistics are given by coun- 

 ties as to the total number of miles of public roads, together with those which 

 have been surfaced, and the expenditure in mone,y and labor as i)ropert,y and 

 lai)or tax. 



An exijerinient in dust prevention {Engln. Rec, ->// (lOOG), Xo. 12, p.-Ul). — 

 Experiments liy the State engineer are being carried <»n near 'I'roy. N. Y., on 

 the prevention of dust on a road running through a village of considerable 

 population, where the dust nuisance is very annoying. 



The means employed are as follows: "Tar, of about the consistency of 

 molasses when cold and fluid when heated, is sprinkled over the road surface. 

 The low sj)ots in the road are then filled with screenings, which are consolidated 

 b.v the tralhc before the second application of the tar is made. This process 

 is rei)eate(l a third time, and is said to result in a practically dustless highway, 

 which will not need another treatment for a year or more. The tar employeil 

 is specially prepared for the purpose by boiling until all its water has been 

 driven off. so that it is not likel.v to foam when heated for application to the 

 roads." 



Tar and oil for road impi'ovenient : Report of progress of experiments at 

 Jackson, Tenn. ( r. ^S". Dept. Af/i:, Office Pub. Roads Cite J/T, pp. 8). — In this 

 circular are reported results of experiments with coal tar, Texas oil and its 

 residuums, in the improvement of macadam and earth streets and roads. The 

 tar was applied during hot weather to the repaired, cleaned, and thoroughly 

 dried surfaces of roads in and near the city of Jackson, Tenn. The tar was 

 kept at a temperature of 200° while being conveyed over the roads in a tank 

 wagon, from which it was distributed over the road surface by a hose with 

 sijecial nozzle and spread evenly in a thin layer b.v laborers using stiff brooms. 

 The tar was absorbed by the road in 8 or 10 hours, after which a light coat of 

 sand or sci'eenings was evenly spread over the surface and the road rolled by 

 steam roller. The average quantit.v of tar used per squ.-ire yai'd was 0.-15 gal. 

 and labor cost $0.0050 to .$0.0005 per square yard. 



It is stated tliat " after more than 7 months, including the winter season of 

 100.5-G. the tariTd I'oads and streets are still in excellent condition. They are 

 hard, smooth, and resemble asphalt excei)t that the.v show a more gritty 

 sui'face." By sections cut from the streets it was found that the tar formed a 

 matrix of 1 to 2 in. ir. thickness, in which the individual stones were embedded. 

 The tar is said to have antiseptic qualities, to make the road as dustless as 

 asphalt, and to lessen greatly the noise of traffic. 



In the experiments with oil on city streets, 0.48 gal. was used per square 

 yard at a cost for labor of .$0.0057 per square yard. On the county roads the 

 respective items w(>re O.-'IS gal. and .$0.0033. The oil was applied to the "dusty 

 11125— No. 3—00 M 7 



