358 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1934 



painstaking research, and it is believed to be the first attempt to por- 

 tray in model form such a variety of information. The model is 4 

 feet wide by 8 feet long, and is on a scale of i/^ inch equals 1 foot. 



The numbers on the perspective drawing (fig. 4) are a key to the 

 model and are inclosed in brackets in the following description : In 

 the foreground of the model at [1] the administrator of the work 

 {curator operis) is seen discussing ways and means for building the 

 road shown on the flat plans {depictae species in membranulis) held 

 by the contractor (manceps) . The third member of the group, hold- 

 ing the roll of plans under hi^ arm, is the engineer (architectus) . At 

 [2], one of the engineer's assistants is alining, with a grorna {10), 

 a stake being driven by another assistant at [3]. A member of the 

 surveying party is shown at [4] running levels with a chorohates 

 {11) while his assistant holds a leveling rod at [5]. 



The model represents a typical roadway on firm upland terrain. 

 Where marshy regions or unstable foundations were encountered, 

 the Roman engineers first built timber-work foundations called con- 

 tignata pavimenta. The timber substructures themselves were called 

 contignationes. The planks in the flooring were termed coaxationes 

 or cessationes and were made of an oak called aesculus, because this 

 wood did not warp or shrink. They covered this timber flooring 

 with a bed of rushes, reeds, or sometimes straw to protect the wood 

 from the destructive effect of the superimposed lime, mixed with 

 other materials. Upon this stratum of reeds or straw was laid the 

 statunien or foundation, and the remainder of the construction was 

 prosecuted in the same manner as on the firm ground, with the excep- 

 tion that the total thiclaiess of masonry seems to have been reduced 

 in order to lessen the dead load of the roadway upon the marshy 

 subsoil. 



Excavation of the foundation. — Upon solid ground the margins 

 of the roadway were marked by two parallel furrows of a wheel 

 plow {aratrum cunnis), as shown at [6], about 40 feet apart. Fol- 

 lowing the location of these furrows, two parallel trenches {sulci or 

 fossae) were excavated [7] to determine the nature of the subsoil 

 and the depth to a solid foundation {greiniwn). The excavators 

 {fossores) used a shovel {pala), and a combined mattock and pick 

 {fossorla dolahra). Then the excavators aided by a porter {hajulus) 

 with a basket {aei'o) upon his back, shown at [8], removed the earth 

 between the trenches to the level of the roadbed {gremium) . A ramp 

 {pons) was used by the porter for reaching the elevation of the 

 undisturbed ground surface. 



C onsolidation of the foundation. — Where unsuitable material was 

 encountered, it was removed and replaced with firm subsoil which 

 was thoroughly tamped with the beetle {pavicula) indicated at [9], 



