REPORT OF THE SECRETARY OF AGRICULTURE. LXI 



STUDY OF SUGAR-PRODUCING PLANTS. 



The sugar laboratory of the Bureau of Chemistry continues to study 

 all the chemical problems relating to the production of sugar-producing 

 plants and the manufacture of sugar therefrom. The chief part of the 

 work is devoted to the study of sugar beets and especially to the 

 influence of environment upon the sugar content thereof. This study 

 is pursued S3^stematically, in collaboration with the agricultural experi- 

 ment stations, and has already revealed in a definite way the influence 

 of the chief factors of environment, viz, temperature, sunshine, and 

 soil, upon the sugar content of the beet. 



Great interest has also lately been awakened in Georgia and Florida 

 looking to the extension of the culture of sugar cane in those localities, 

 and the Bureau of Chemistry has taken up a systematic examination 

 of the soils on which the cane is grown and an analysis of the canes 

 produced. 



STUDY OF ROAD-BUILDING MATERIALS. 



The laboratory for the study of road materials, established to coop- 

 erate with the Office of Public Road Inquiries, has been fully organized 

 and is now one of the important sections of the work of the Bureau. 

 The physical and chemical stud}^ of the materials used in building- 

 roads* will lead to not only greater economy in road construction, but 

 far greater durability. The cementation value of the materials used 

 for surfacing a road differs so widely that the efficiency of the road 

 depends upon the nature of this material. The investigations of this 

 laboratory will show to road builders the exact character of the mate- 

 rials which it is proposed to use for surfacing and lead them to choose 

 those which will give the highest efficiency. 



The laboratory has in no way been advertised, except in the exhibit 

 made at the Pan-American Exposition, owing to the limited facilities 

 for canwing on the work; but even with this necessary precaution it 

 has been impossible to keep pace with the heavy demand for tests. 

 Samples have been received from all parts of the United States and 

 even from our foreign possessions. 



At the present time the laboratory has the equipment and facilities 

 for testing all varieties of macadam rock, gravels, and clays, and in a 

 short time the equipment for testing paving brick will be ready. In 

 the testing of paving brick, not only will the physical properties of 

 the manufactured brick be determined, but a thorough study will be 

 made of the methods and materials used in making the various types 

 of brick to aid the manufacturer as much as possible in improving his 

 products. The prime object of this laboratory is to aid road builders 

 in selecting the best available materials for their roads. 



When it is considered that the cost of properly constructed macadam 

 roads is from $3,000 to $10,000 a mile, and that the cost of paved 



