50 Director's Annual Report. 



A hoist works from the ground floor to the Photographic depart- 

 ment. A cistern on the upper roof supplies automatically the 

 photographic sinks in case of temporary interruption of the main 

 water supplv. 



Work of construction commenced early in January, 1910. 

 The soil was removed to the suitable level and parallel lines of 

 terracotta drain pipe laid through this area : the excavation for the 

 wall and pillar foundations being carried down to the bedrock. 

 In one place the soil proved to be decomposed lava that had later 

 been permeated by sulphurous gases whose action on the calcare- 

 ous portion of the earth had formed beautiful crystals of gypsum 

 in abundance, of tolerably uniform size and frequently twinned. 

 Otherwise the soil did not differ from that of the rest of the yard. 



Waterproof material was carefully spread over the leveled sur- 

 face and the concrete floor poured on this. The rotary mixer and 

 the hoist were actuated by internal combustion engines. The 

 greatest care was taken to have the ground floor free from damp- 

 ness by external as well as the internal subsoil drains mentioned, 

 quite independent of the drainage system of the building. So far 

 this has proved satisfactory. That the other floors might be solid 

 work was continued through the night that the pouring might be 

 continuous. 



The Kahn system of reinforcing was used, and a thicket of 

 steel rods, wired together, rose from the box moulds as the build- 

 ing progressed. Much of this ma}' be seen in the illustrations 

 showing the progress of the work. The floors and partitions were 

 strengthened by expanded metal, and the concrete beams had 

 suitable steel skeletons to take the stress. The stairways also 

 were concrete, and indeed the whole building was monolithic. 

 The plans of the floors and the views given with this brief account 



will make the structure intelligible. 



[74] 



