376 MISCELLANEOUS STRUCTURES 



from sand, dust and dirt and must be applied perfectly dry while the 

 cement is hot. 



The structural features of the glazing in the windows and lights 

 of the monitor roofs are fully shown by the drawing of Figs. 177 and 

 178. It will be noted that the sash in the side walls of the monitor roofs 

 are hung on pivots at the middle of each side. There is a similar ar- 

 rangement of sash in the upper side wall windows of the side roofs 

 overlooking the low middle roof, except that the sash in alternate bays 

 only are pivoted. These latter sash are to be provided with "Brand's" 

 sash openers, with chains operated from the crane runways and ar- 

 ranged to open all the sash of one bay at one time. The feature most 

 worthy of note, however, is that the sash in the side walls of the moni- 

 tor roofs are to be operated by compressed air power from a central 

 point on one of the side walls of the building near the floor. The sash 

 will be operated in sections about 75 feet long and the piping and 

 valves will be so arranged that any one or all of the sections can be 

 operated at one time. 



Next to the framework of the building, the structural features of 

 most interest are perhaps the pit and floor construction. This is shown 

 in detail by Fig. 180. In constructing the floor the ground inside 

 the building will be carefully leveled and well tamped and puddled if 

 necessary. The entire area of the main building, except under the pits, 

 where cement concrete will be used, and under the railway tracks, where 

 stone ballast will be used, will then be covered with a layer of bituminous 

 concrete. This concrete will be composed of well screened cinders and 

 No. 4 coke oven composition mixed in the proportion of at least one 

 gallon of composition for each cubic foot of cinders. This composi- 

 tion is to be laid hot and well rammed. Yellow' pine floor sleepers, 

 6x6 ins. square, will be bedded in the bituminous concrete at intervals 

 varying from 4 ft. to 5 ft. transversely of the building. To these string- 

 ers there will be spiked an under floor, or lining, of hemlock plank 

 planed on both edges and on the upper side. On top of this lining 

 there will be laid a flooring of i^g x 4-in. maple boards of a uniform 

 and regular width, planed on top and both edges, worked on the back 

 to a depth of i-i6-in. and a width of 2^4 ins., laid across hemlock floor, 

 bored on a slant for nailing and face nailed with I2d. nails, the two 

 lines of nails in each board being staggered. The nails will be placed 

 in lines on each side of the board and not over 16 ins. apart, and the 

 nails in one line will be opposite the middle point between the nails in 

 the opposite line. 



