320 CARNEGIE INSTITUTION OF WASHINGTON. 



generous offer of assistance by Dr. Henry S. Washington, of the Geophysical 

 Laboratory, whose earlier work in the archaeological field renders him espe- 

 cially fitted for the task. The months of June and early July were largely 

 devoted to a review of the whole field from this standpoint and the choice 

 of the materials necessary for this investigation. It is hoped that, in con- 

 nection with his valuable work on the volcanic stones of the region, Dr. 

 Washington, in association with Dr. Tenney Frank, Professor of Latin in 

 Johns Hopkins University, may be able to make also a study of the stones 

 used in the greater Roman monuments. 



A valuable series of experiments has been undertaken during the year by 

 Professor Alfred H. White, head of the Department of Chemical Engineer- 

 ing of the University of Michigan, to determine the water absorption of the 

 Roman bricks and the changes in volume of the mortar of the different 

 periods. The results of this investigation, while primarily of interest to 

 modern engineers, will, it is hoped, furnish additional data for the classifi- 

 cation of these materials. 



An alarming change has taken place, in the last decade, in the condition of 

 the monuments of most importance for the study of Roman construction as 

 well as Roman history. Many of these monuments are at present threatened 

 with complete extinction or such extensive restoration as to render them 

 almost valueless for study. While this is most noticeable in the earlier 

 monuments, especially those made of the more friable tufas, many of the 

 imperial walls must be very shortly restored to prevent entire collapse. The 

 scientific investigation and publication of these remains as rapidly as possi- 

 ble is imperative before newer excavations are undertaken. 



