EEPOET OF THE ARCHITECTS. 171 



expensive fire-proof floors, were fitted up, the lofts in the 

 corner-pavilions were converted into additional finished 

 stories at a cost of. $4, 500 00 



The covered spaces in front of and sheltering the four main 

 entrance doors were inclosed by ornamental iron gates 

 at a cost of 1, 804 08 



All the brick work of the extensive facades was oiled and 

 penciled at a cost of 2, 750 00 



Terraces were formed to regulate the grades of the ground 

 around the building at a cost of 2, 428 00 



There was expended for cut stone on the approaches to the 

 main entrance 1, 286 00 



Total $14,733 08 



The conditions imposed upon us to keep within the appropriations 

 have been complied with in good faith. A substantial fire-proof build- 

 ing has been comiileted at a less cost per square foot of the inclosed 

 area than that of the temporary buildings erected for the International 

 Exhibition in Philadelphia in 187C. 



The principle adopted to have all the windows in side walls and lan- 

 terns glazed with two sheets of glass, having an intermediate air-space, 

 has led to favorable results, and it is desirable to extend the same feature 

 over the under sides of the roofs in the halls by the introduction of light 

 'iron ceilings about 1^ inches distant from those plastered undersides ; 

 the intermediate air-space in this case to be packed with a non-conduct- 

 ing fire-proof material, such as mineral-wool or its equivalent. This 

 will secure for the building a very pleasant temperature in summer, 

 reduce the expense of heating the huge building in winter, and remove 

 any tendency towards condensation on those exposed undersides during 

 the rapid changes of temperature and hygrometric condition of the 

 atmosphere peculiar to this climate and locality. 



Having given a technical description of the design and construction 

 of the new building in our last report, we now report specially on the 

 theory, practice, and results of warming the building. In consideration 

 of the great cubic contents of air inclosed in the building, and the com- 

 paratively very few sources of vitiation of the same, the system of heat- 

 ing by direct radiation has been adopted. For winter ventilation the 

 spires of eight towers and the lanterns of halls and dome are made 

 available whenever necessary, and for summer ventilation a sufficient 

 number of imi)roved iron sashes pivoting in iron frames have been 

 added and inserted in the windows of the side walls and the lanterns of 

 the building. 



The heating coils and radiators are placed in the rooms to be warmed 

 and heat the air by contact with the radiators ; the surrounding walls 

 and solid objects absorbing a certain amount of radiant heat and again 

 heating the air by contact. 



