SCIENCE IN HIGHWAY CONSTRUCTION 337 



The methods of making the above determinations have been elabo- 

 rated during the last twenty-five years to such an extent that they may 

 be relied on for the purpose for which they are used, although they will, 

 no doubt, be improved in the future, as they have been, from time to 

 time, in the past. At present they are sufficient, not only as furnishing 

 data which will form a satisfactory basis for arriving at the character 

 of any bituminous material, but also as a means for control of the uni- 

 formity of any supply which may be selected, and for regulating its use 

 in actual highway construction. 



From what has been said it can be seen that the role of the chemist 

 in highway construction to-day, where bituminous materials are be- 

 coming so important an element of it, is an important one, that science 

 can contribute much to the improvement of highway construction, and 

 that these contributions should not be neglected where it is proposed 

 to do the highest type of work, and to produce a highway surface which 

 shall resist the heavy travel to which they have been subjected since 

 the advent of the motor car. 



