MEMOIR OF DANIEL TRE A DWELL. 



399 



plaster well secured to the laths, which were held by light joists without beams i 

 floors, offered little food for flames. The gallery floors were supported entirely by bai 

 of wrought iron, and guarded by a light iron balustrade. The two ranges of (iothic 

 columns, of brick, supporting the roof, and for that purpose rising from the founda- 

 tions in the cellar through the ceiling, were as safe from fire as could be desired. 

 The walls, which were furred, lathed, and plastered, wore objectionable; in the 

 spaces between them and the stonework fire could spread, even if that space wen 

 cut off from floor to iloor by incombustible materials. The window-frames wen 

 to have been of iron, but wood had been substituted. 



The first condition for safety was the placing of the beating apparatus where 

 it would be effectually cut off from the main hall of the building. This was done 

 by making the floor of the hall of a series of groined vaults of brick, supported upon 



large square columns; through this the only open in > were for the steam-pipes lor 

 heating. The whole ground was damp, the arches were low, and the windows small 

 consequently, without inducement to place here woodwork or inllammable matter 

 of any kind to interfere with the sole purpose to which the cellar was to be devoted, 



namely, the heating apparatus. The cellar of the west transept, which is vaulted, 



like the cellar of the main building, contained a small hot-air furnace, and a narrow 

 flight of stairs, the only communication with the room above. The spandrels of the 

 arches were filled up, and upon them is laid a single floor of hard pine. 



The roof is constructed without wood, except the boards or laths to which the 



slates are fastened. The place of rafters is supplied 



by trusses mad 



lit bars of wrought iron, which are supported by the walls and by iron purl 



~- ~„..~ ~~ .,*.V~ Q 



ranged through the building upon the tops of the Gothic solid brick column-, which 

 rise from their foundations in the cellar through the ceiling for this purpose. The 

 thrust of these trusses is prevented by iron rods, which take the place of the beams 

 in wooden roofs. Its weight is about half that of a wooden roof of the same size, 

 and equal to bearing the weight of a body of men standing close to each other, and 



sp 



great as that enclosed by the building. TI 



and therefore affords no place for storage. 



In selecting a heating apparatus, Professor Treadwell was strongly in favor of 

 steam as the vehicle. Hot air and hot water were both considered. The first, 

 although the simplest and at that time generally used for houses, is objectionable. 



Its dryness and deleterious gases are difficult to avoid. They are apt to injure 

 the bindino- of books : the leather becomes dry and brittle, the covers are warped, 

 and if much used soon break. It often contains smoke from within, and dust from 



