446 



Technical Problems. — The study of track fastenings, including common 

 and screw spikes, and tie plates, and the relation of these to the strength 

 of ties is in progress. Laboratory tests are supplemented by service tests 

 in tracks of railroads under operation. 



TECHNIQUE OF TESTS AND THE ORGANIZATION OF THE LABORATORY WORK. 



The methods and records and organization are now well developed. 

 The results of experience for the past six years are contained in Circular 

 38, (Revised), entitled '"Instruction to Engineers in Timber Tests." Re- 

 cently a department of microscopic examination of wood has been added to 

 study manner of failures in the tissues, changes in structure resulting from 

 heat treatment, location of preservative fluids and allied problems. 



Purdue University. 

 Lafayette, Ind. 



