BUREAU OF CHEMISTRY. 149 



cider will be continued. Some time will be devoted to the study of 

 polariscopic and reducing methods for the determination of sugar, in 

 cooperation Avith tlie sugar referee of the Association of Official Agri- 

 cultural Cliemists. 



The most important new line of work that will be inaugurated will be 

 the study of infant and invalid foods, of which a large number is now 

 on the market. This will be taken up early in the autumn, and will 

 probably occupy the time of a portion of the force during the full 

 calendar ye-dv. An examination relating to nonfermented beverages 

 and flavoring extracts on the market will also be made. 



ROAD MATERIAL LABORATORY. 



During the current fiscal year the same tests referred to in the 

 first part of this report will be carried on, and the demand for them 

 will doubtless be much greater. Besides these tests, the necessary 

 appliances have been installed for testing paving brick ; and as the use 

 of brick for road paving is increasing very rapidly, and as the testing 

 of brick is most essential, this work will doubtless be one of the impor- 

 tant features of this laboratory. 



It is also intended to make certain investigations in the mixing and 

 burning of clay for the purpose of obtaining methods for getting the 

 necessary properties essential to good paving brick. 



The testing of cements and concretes will also be an important part 

 of the laboratory work, as concrete is not only used extensively in 

 road foundations, but for drainpij)es and sidewalks as well. The 

 equi]3ment for carrying on this work has been partially installed and 

 the work will soon be taken up. 



Wood blocks have long been used in Europe with great success for 

 paving streets, and their introduction into this country, with modern 

 methods of preserving the wood, is met with favor. When properly 

 treated there is no material better suited to heavy traffic than wood 

 blocks. They are sanitary, and probably give less noise and dust 

 than anj' other form of j)avement. The importance of investigating 

 the proper methods of preserving wood is so essential that the subject 

 has been taken up in collaboration with the Bureau of Forestry, and 

 it will be made an object of study during the current year. The 

 Bureau of Forestry has supplied this laboratory with two most essen- 

 tial testing machines for carrying out the j)hysical tests on wood blocks, 

 and the dendro-chemical laboratory of this Bureau will investigate 

 the chemistry of the subject of wood preservatives. 



The necessary expert assistance during the year will more than 

 absorb the total allowance which has been made, and the additional 

 funds necessary, togetlier witli all incidental expenses of the labora- 

 tory, will be supplied from the miscellaneous funds of the Bureau of 

 Chemistry. 



DENDRO-CHEMICAL LABORATORY. 



The work outlined for this laboratory for the present year is as 

 follows : 



(1) Continuation of the analytical studies on the composition of the 

 wood and bark of certain American oaks and hemlocks. 



(2) Extension of the work on American wood pulps and wood-pulp 

 papers in connection with the investigation on the availability of cer- 

 tain woods as a source of wood pn\p, the ultimate object being the 

 creation of a paper-testing laboratory which shall exercise an intelli- 



