Smithsonian Report. I''30.--Gr.iy anil I Id>;rn 



Plate 9 



1. Gang of "Sand Hogs" in Liue 

 Waiting to check in for work in compressed air. Canal Street land shaft and .lir locks, South Tunnel. 



2 HAULING A Car of Muck out of a Muck Lock. South Tunnel 



