EEPORT OF THE AKCHITECT. 



Washington, January 6, 1868. 

 SiKS : I have the honor to report the progress made in the reconstraction of 

 the buildings daring the calendar year 1867. 



The absolutely fire-proof roof of the main building, consisting of a slate cover- 

 ing, plastered inside and fastened by wire to a well-braced WTOught-iron frame, 

 has been firmly put in place. Many difficulties had to be overcome, since the out- 

 lines of the building, more especially the shape of gable walls and topping out of 

 side walls, on which that most important feature of the mediseval roof, the sys- 

 tem of guttering, depends, were prearranged upon the more pliable plan of a com- 

 bustible frame and wooden sheathings. However, no pains were spared to 

 accommodate the new conditions to the original architecture of the biiilding. 

 The different hips ix,\3 valleys were made secure and water-tight by wide strips 

 of sheet-copper and sheet-lead laid upon a solid foundation of sheet-iron of proper 

 width, fastened by wire to the rafters. The gutters consist of wrought-iron, 

 rolled into proper shape, and of a section vouched for by the Phoenix Iron Com- 

 pany. The connections of the sections of gutters, lengthwise, have been made 

 so as to allow for expansion, and the connections of the gutters, sidewise, with 

 the slate roof are effected by galvanized sheet-iron plates riveted to vertical 

 flanges on the inner side of the gutter, and bent so as to follow up the pitch of the 

 roof, sustained by the lowest courses of iron purlines for the slating. The mode 

 adopted has effectively carried off the water of the heaviest rain storms of the sum- 

 mer, but, being of a novel design, has not fully stood the test of an extraordinary 

 snow-storm followed by a rainfall which was freezing as fast as it came down. 

 Tliis action of the elements caused a thorough freezing up of the northern gutters 

 encased inside the battlements of the side wall, and with the consequent effect of 

 the sun upon the upper part of the roof, the melted snow in its downward course 

 forced its way underneath the frozen face and, for want of an outlet, backed up 

 underneath the galvanized sheet-iron described above. Plans have been laid 

 before the building committee with a view to remedy this defect as developed by 

 severe tests. 



The ridge of the roof, another important feature, has been effectively secured 

 by a layer of sheet-lead, capped by rolled iron, shaped to tlie angle formed by 

 the ridge of roof and batted down to the roof frame. 



In connection with the frame of the roof, for considerations of solidity as well 

 as of economy, all the necessary and somewhat complicated iron stays, links and 

 purlines have been inserted, forming the outlines of an appropriate and well- 

 shaped ceiling in keeping with the features of a fire-proof hall, 200 feet in 

 length by 50 feet in width. Whilst the details of this ceiling are left an open 

 question for the decision of the committee, its main featm-cs consist of a boldly 

 coved and bracketed cornice, surmounted l)y broad panelled friezes, the inner 

 meml)ers of which are formed so as to sul)dividc the whole ceiling into three 

 panels, each extending through the whole width of the building and worked out 

 again into more minute details. 



After the roof was well secured, the tracery of the double w'indows in the side 

 walls was carefully taken out, the numerous weakened parts of the cut stone 

 work supplied by new material and workmanship, and the whole work reset, 



