178 REPORT OF THE ARCHITECTS. 



The spacious platform in front of the northern main entrance waslaitl 

 with a floor of ornamental marble tile. 



A sewer has been constructed through the Smithsonian grounds, di- 

 rectly to the main sewer along North B street, and the building is now 

 disconnected from the overcharged branch sewers of the city. 



All the plumbing fixtures necessary or proper to be introduced in the 

 building for safety, for the accommodation of visitors, as well as officials, 

 such as fire-plugs, sinks, wash-basins, water-closets, and urinals, were 

 provided for and constructed during the season in strict accordance with 

 the present requirements of sanitary science. 



A large number (thirty-two) of the sash-windows in the lanterns of 

 the main and square halls have been made movable in sections by sim- 

 ple mechanism worked from the floors of the halls. This improvement 

 has proved to be a valuable agent for summer ventilation during the hot 

 spells peculiar to our climate. | 



Several partitions of fire-proof concrete material have been con- ^ 

 structed in the two eastern corner pavilions for the better accommoda- 

 tion of the service. 



An important improvement has been introduced in one of the outside 

 halls by the construction and hanging of a comely iron ceiling under- 

 neath, and parted by an air space, from the roof. The double ceiling 

 has added materially to the sanitary advantages of the building, and it 

 is highly desirable to have it extended over the whole building. 



The slates of the roofs are hung to iron purlines, and are plastered 

 on their under side with a heavy coat of mortar. During rapid changes 

 of the temperature, moisture arising from the process of condensation of 

 aerial vapor appears occasionally on this plastered surface which forms 

 the ceiling of the principal halls ; this will be obviated by the hung iron 

 ceiling with air space between it and the plastered slates. i| 



The roofs and ceilings of the lower halls are formed by sheet metal 

 laid upon fire-proofed gratings, which are again plastered on the under 

 side. The adherence of the j)lasterer's mortar to the greasy fire-proof j 

 composition has proved to be insufficient, and it fell in a number of 

 patches. The whole surface so covered, aggregating about 3,600 square 

 yards, and costing about $720, was hence removed, and the proposed 

 iron ceilings will incidentally serve to hide the unsightly surface of the 

 exposed gratings. 



The action of the rapid changes of the temperature during our sum- 

 mer months, in causing expansion and contraction of building material 

 disposed in great lengths throughout this extensive structure, has occa- 

 sionally^ baffled the provided safeguards. It has been carefully watched, 

 and small imperfections have been remedied wherever and as soon as 

 they appeared. With comparatively little more attention they will be 

 completely under control. 



