The Birmingham age-herald., 1908-10-12
IMPORTANT WORK
 FOR GOOD ROADS

l Washington, October 11.-(Special)-
 Dust Preventatives.a by Provost Hub
 bard issued as Bulletin No. 34 United
 States office of public roads, is the latest
 contribution to literature on road con- struetion and maintenance. MT. Hub
 bard's paper has been prepared to meet | the growing demand by road engineers for specific information on the important subject of dust prevention. He has made a research of all literature on the subject, experimenting this with the results of ac- tual experiments made by the office of public roads. Interest has been recently reawakened in the problem of the pre- vention of dust on country highways, the well nigh universal use of the automO- bile being responsible for the additional study and experiments. Road engineers are now agreed that the automobile when moving at a high speed is destruetive to macadam roads, the broad soft tires lift ing the rock dust and scattering it over adjacent fields. A road robbed of this fine surface binding material retrogrades rapidly That indictment now lies against the modern motor car, but on the other hand the introduction of the machine has done much to awaken an interest, not merely in dust prevention, but in the en- tire subject of road improvement There in the automobile is entitled to credit. It is superfluous to add that clouds of dust are annoying, not only to the users of the highways, but to the residents whose property borders upon them and that they affect public health and depreeiate the value of property
 Mir. Hubbard, in his discussion of meth ods of overcoming this condition divides the problem into two parts, first by ap- plying materials that will hold the dust down. and second by adopting form of road construction that will reduce dust formation and the wear of roads to minimum. These he says may be attained by temporary and by permanent bindersAthose under the temporary classification being materials which must be frequently applied. the permanent" ones being the heavier materials which through one application maintain the road surface in a dustless condition for a season.
 The author describes the manufacture and properties of tar, pointing out the differences between tar from coke ovens, from gas plants, refined coal tar, and water-gas tar. chapter on the appli- cation of tars follows and brings out the fact that the painting of road surfaces with tar was considered in France as aa Fl a1f ba rlr begun in earnest until 1902. The chapter contains clear directions for applying the material to the road, both used a palliative and for use in permanent con- struction. Much data Is given as to cost and quantities of materials, and exam pies are cited of successful roads built by the aid of various tars. After the con- sideration of tars, the author deals with the classification and properties of oils and gives the location of all the produc- ing fields in the United States. He de- scribes the method of refining oil and the character of the residuum. and draws comparisons between crude oil and by products of the refined oil.
 A chapter dealing with water and salt solutions including calcium chloride fol- lows, and the portion of the bulletin rela- ing to materials terminates with chap ter on temporary tar and oil binders, emulsions, and similar preparations.
 MT. Hubbard concludes his treatise by calling attention to the importance of careful selection of dust preventatives, making valuable suggestions for the choice of materials for treating country roads, suburban and park roads respec- lively. He gives an exhaustive explana- ton of the methods of examination, and outlines tentative specifications for the use of dust preventatives. The bulletin should do much toward directing experi- mental work in this important field along proper lines.