586 EXPERIMENT STATION RECORD. 



highway corumission and excerpts from the specifications for State-aid roads 

 in that State are also included. 



Highway improvement in Vermont, C. W. Gates {Ann. Rpt. [Bd. Agr. Vt.~\, 

 28 (1908), pp. 67-72, figs. 8). — In this report of the State highway commis- 

 sioner there is an outline of Vermont's State-aid policies and notes on the im- 

 provements accomplished in the past year under them. The greatest mileage 

 in the State-aided roads now consists of improved gravel roads with Telford 

 foundation, and several of this type are illustrated. 



Dust preventives, P. Hubbard (U. S. Dept. Agr., Office Pub. Roads Bui. 3^, 

 pp. 6-'i, pis. 3, figs. 6). — This bulletin is intended to furnish specific information 

 concerning the materials and methods employed in dust prevention on all 

 classes of roads. It is based on a review of all available literature supple- 

 mented by results secured from actual experiments conducted by the Office of 

 Public Roads. Two general methods of attacking the dust problem are, (1) to 

 apply material to hold down the dust, (2) to employ methods of construction 

 designed to reduce its formation. This bulletin deals with the first method 

 and the materials used are discussed in two classes; water, salt solutions and 

 the lighter oils being considered temporary binders, and the tars, solid and 

 semisolid materials, permanent binders. The bulletin concludes with a chapter 

 on methods of examination and tentative specifications for the various pre- 

 ventives. 



Irrigation in Mexico (Bol. Soe. Agr. Mexicana, 32 (1908), No. ^2, pp. 821- 

 825). — This article contains the terms of a contract recently let by the Mexican 

 Government for the enlargement and construction of irrigation works includ- 

 ing dams, canals, and reservoirs. 



Yuma irrigation dam, D. A. Willey {Sci. Amer., 99 {1908), No. 18, pp. 

 302-303, figs. 3). — This describes some of the difficulties which presented them- 

 selves in this project and the way they were overcome, resulting in the success- 

 ful control of a river which is liable to fluctuations of as much as 30 ft. in a 

 week, and which flows through a channel of soft silt which has been accumu- 

 lating for centuries. 



A drainage system was considered necessary in conjunction with the irriga- 

 tion works because of the flatness of the land and the high ground-water level, 

 and consists of a main canal througli the center of the irrigated areas, utilizing 

 the natural drainage channels when possible. 



A new scraper excavator (Engin. News, 60 {1908), No. 18, p. 483, figs. 2). — 

 There is described a drag scoo}) bucket so designed that it will not " ride over " 

 hard material. A heavy bail is rigidly attached to the side, which can, however, 

 be set at various angles to the mouthpiece, thereby allowing the depth of cut 

 to be gauged. 



Th.e applications of the motor in agriculture {Auto. Agr. [Paris], 1908, No. 

 13, pp. 5-7, p'gs. 5). — In this article the author briefly discusses the require- 

 ments of practical motor traction engines, with an analysis of the forces in- 

 volved. It is stated that special attention should be given to sec-uring the best 

 point of application of the power, as in most engines the greater part is required 

 to transport the motor itself. In this respect machines fltted with drums have 

 an advantage over those in which the plows are connected directly. 



Traction motors {Agr. Prat. Pays Chauds, 8 {1908), No. 67, pp. 288-297, 

 figs. .',). — Two types of gasoline engines, fitted with hoisting drums for hauling 

 plows, etc., and two types of gasoline traction engines and their various appli- 

 cations are described, with tables showing the results of efficiency tests. 



Traction culture machines, V. Fremier {Auto. Agr. [Paris]. 1908. Nos. 11, 

 pp. 5-9, figs. 10; 12, pp. 6-11, figs. 16). — This is a series of articles describing 

 the different types of engines which have been invented for machine cultivating, 



