Chronology 9 



ever, the gradual expansion of the activity led to ever-increasing specializa- 

 tion.'^ 



Screen towers and rigging facilities for obtaining velocities of projectiles at up 

 to 17° angles of fire were constructed in front of the Main Battery emplace- 

 ments. The towers were to become the dominant physical characteristic of the 

 Proving Ground. Additional facilities servicing the Main Battery were two 

 gantry cranes, capable of handling 200 tons with trackage to service all major- 

 caliber emplacements, and a locomotive crane with a 150-ton capability. A 

 bombproof building at the Main Battery was positioned to allow for a powder 

 stowage magazine, powder weighing room, constant-temperature powder 

 stowage room, and office space. A small building also served as an ordnance 

 workshop and storeroom.^" 



Expansion of the Main Battery facilities was begun on a small scale in 1926 

 and continued through 1935. During this time, two additional major-caliber 

 emplacements for multiple gun mounts, one additional minor (or intermedi- 

 ate)-caliber gun emplacement, and two major-caliber gun parks were added. ^' 



Maintenance of the river range at Dahlgren was formalized in 1920 with 

 establishment of the Range Section, which at that time consisted of four indi- 

 viduals: a section head, an individual responsible for keeping records, and two 



Construction of Main Battery at the Lower Station. 



