Evening Republican, Volume 18, Number 189, Rensselaer, Jasper County, 12 August 1914 — DYNAMOMETER MEASURES SAVING GOOD. ROAD REPRESENTS OVER A BAD ONE [ARTICLE+ILLUSTRATION]

DYNAMOMETER MEASURES SAVING GOOD. ROAD REPRESENTS OVER A BAD ONE

Department of Agriculture’s New Device Will Inform You Just How Hard Your Horse Has to Work—No Longer Necessary to Make Educated Guess of What Constitutes Easy Traveling.

Washington, D. C. —By means of a new device known as the dynamometer, the department of agriculture is now able to measure exactly the saving that a good road represents over a bad one. In the future it will be no longer necessary to make an educated guess at what constitutes easy traveling. With the dynamometer It is possible to ascertain with scientific accuracy the resistance offered by different kinds of road surfaces, grades, vehicles and tires. The dynamometer registers on a record, which is In appearance not unlike that of a self-registering thermometer, not only the pull necessary to draw the wagon but the distance traveled and the time consumed In the trip. All this is automatically recorded by a brass pencil point on a long roll of sensitized paper, which is arranged to unroll in such a fashion that -240 inches of record represent a mile of road travel. The movements of the pencil are governed by the amount of compression of two coll springs. For every 500 pounds of draft exerted on the tongue of the wagon the pencil makes a mark an Inch long. In addition to this dots appear on the surface of the paper at Intervals of 15 seconds. To take two concrete examples, Fig. 1 is the record of a stretch of average road 110 feet in length traveled by a wagon with tires 2% inches in width. This distance was traversed in 25 seconds with an average draft of 408 pounds. This means that it took 3 3-10 horse power to draw the wagon under these condition. Fig. 2 is the record made by the dynamometer in traveling 110 feet on a steep uphill heavy road with tires of the same width. The difference is startling. In this case it took 29 seconds to go the distance, but it required an average pull of 1,077 pounds instead of 408, or stated in terms of horse power 7 4-10 instead of 3 3-10. There is, of course, nothing new In the fact that it is easier to pull a heavy load over a level road than it is up a bad uphill one. It is well known, for example, that when it requires a draft of 100 pounds per toss to haul a load on a level stretch it takes approximately four tlmeis as much power to draw a load up a ten per cent grade (10 foot vertical in a hundred foot horizontal). On the other hand, for a

matically for example in this way. To lift a ton one foot high requires 2,000 pounds -of energy. If the road is of such a character that it offers a hundred pounds of tractive resistance per ton the same energy will roll the ton a horizontal distance pf 20 feet To save one foot of grade the road ipay therefore be lengthened 20 feet without increasing the amount of energy required. If the tractive resistance of the road is less than 100 pounds the distance it may economically be lengthened is, of course, lessened also, and vice versa. The dynamometer is the only way in which this tractive resistahce can be exactly measured, and thus it enables road engineers to do their work with absolute scientific accuracy. Interest in good roads has been increasing with extraordinary rapidity in the United States during the last few years and the expenditures for road Improvement have increased with it Thus in 1904 the total expenditure on all public roads in the United States was >79,771,417. By 1912 this had risen to 3164,232,365.

short time any load that a horse can pull on a level can usually be drawn up a four or five per cent grade. Four per cent, therefore, is usually regarded as the maximum grade permissible in road building. Frequently, however, it would be advantageous to do away with such a grade altogether by means of a detour. In deciding when to do this the dynamometer is unquestionably of great service. The problem may be stated mathel 1 Illi ll* '

That this vast sum should produce the best possible results is obviously of great importance. Hitherto it has been estimated that a large portion of it has gone to waste through ignorance of the right kind of road .to build in different localities or failure to maintain it properly,when built With the aid of the dynamometer all problems of resistance can be studied as a first step toward solving them. The question of durability, of course, it does not touch, but one machine cannot be expected to do In the future it is not altogether impossible that the records of the dynamometer may be translated for the benefit of all concerned into actual dollars and cents. Already there is an abundance of evidence in the possession of the department of agriculture to show the cash value to a community of roads that afe easy to travel on. In Xx>e county, Virginia, for example, a of 10 acres was offered for sale some-years 'ago at |l,Boo. In 1908 the road running to this farm was Improved and since then 33,000 has been refused for the same 100 acres. In Alabama the people of one county voted a 3250,000 bond issue tor road improvement Land at that time was worth from six to fifteen an acre; it is now selling for from fifteen to twenty-five dollars an acre. On the other hand there was a well authenticated story of a Tennessee farmer who was compelled

to let a hundred barrels of potatoes rot in his cellar because of the road to market being Impassable in the winter time. That winter the price of potatoes rose to $1.40 a barrel. Poor roads were entirely responsible for the loss to this man. Instances of this sort could be multiplied without end. Like the dy-

namometer they show that the movement for. good roads is not based on theory and sentiment but is as much a matter of cold business as the proper use of fertilizer or the proper food for live stock.

Figure One—110 Feet of Road.

Figure Two.

Motor Wagon Used by Government In Road Work.