Page:The National Geographic Magazine Vol 16 1905.djvu/112

Rh experiments with fruit stock and buildings and granaries are now under way, as well as cooperative work between the Bureaus of Entomology and Chemistry on the composition of insecticides.

BIOLOGICAL SURVEY

The work of the Biological Survey has been continued along three principal lines: First, investigations relating to the geographical distribution of animals and plants, including biological surveys and the determination of the life and crop belts; second, investigations of the economic relations of birds to agriculture ; third, supervision of matters relating to game preservation and protection and the importation of foreign birds and animals. In carrying out this threefold mission the Biological Survey is divided into three sections — that of geographical distribution, that of economic ornithology, and finally one of game protection and introduction.

IMPORTATION OF BIRDS AND MAMMALS

Constant vigilance is necessary to prevent the introduction into the United States of birds or animals likely to become pests. The permits issued during the year numbered 318, and included 1,470 mammals and 250,000 birds.

ENFORCEMENT OF GAME LAWS

Six convictions for illegal traffic in game were secured during the year under the Lacey act, making 42 convictions secured in cases passing through this department. In Alaska the game law has accomplished two main objects — the shipment of deer heads has been stopped, and the export of heads of big game as trophies has been curtailed.

PUBLIC ROAD INQUIRIES

Object-lesson roads have been constructed with the cooperation of the office of public road inquiries in Arkansas, Ohio, Tennessee, Virginia, and

West Virginia. These were mostly first-class macadam roads. It has also cooperated at several points in the South in constructing experimental roads of a mixture of sand and clay. In the absence of stone and gravel, this mixture may be used to great advantage. Much has been accomplished during the year in the development of good roads by the state-aid plan. The main features of this plan as now adopted in several states are a state highway commission, appropriations from the state treasury to pay a portion of the expense, the balance being divided between the counties, towns, and the owners of property along the improved roads. Since 1890 eleven states in all have provided, in a greater or less degree, the state aid.

Much time has been spent in studying the physical properties of clays in an endeavor to devise methods by which they can be utilized in road making. Of 228 samples of road materials reported during the past year, 35 were clays. Clinkered clay has been successfully used for some time past as a railroad ballast. Experiments were made with samples of the so called gumbo clay from the Yazoo district of Mississippi, and following these experiments the Office of Public Road Inquiries built an experimental road in Yazoo City, which has been reported successful. The Division of Tests has not confined itself to investigations of clays in their use as road material, bu to their useful properties for any purpose, with a view to developing the use of native clays, of which the production already exceeds $2,000,000 annually, while of foreign clays over $1,000,000 worth are imported.

OILS AND ASPHALTUM FOR ROADS

The suggestion of the Division of Tests to road builders throughout the country to make experiments with mixtures of crude oils and crude asphaltum in road building has resulted in some cases very satisfactorily.