92 FEEDING ANIMALS. 



pull, the bottom of the roof cannot spread, and the rafters 

 being properly bridged from the middle to the top, cannot 

 crush, and the whole must remain rigidly in place. Its 

 external form being that of an octagonal cone, each side 

 bears equally upon every other side, and it has great 

 strength without any cross-ties or beams, requiring no 

 more material or labor than the ordinary roof. The plates 

 are halved together at the corners, and the lips bolted 

 together with' four half-inch iron bolts (see fig. 6) ; a brace 

 8x8 inches is fitted across the inside angle of the plate 

 corner, with a three-fourths-inch iron bolt through each 

 toe of the brace and through the plate, with an iron strap 

 along the face of the brace, taking each bolt, the nut turn- 

 ing down upon this iron strap (see fig. 7). Now the hip 

 rafter (t), 6 x 12 inches, is cut into the corner of the plate, 

 with a shoulder striking this cross brace, the hip rafter 

 being bolted (with three-fourths-inch iron bolt) through 

 the plate into the corner post (see fig. 6). Thus the plate 

 corner is made as strong as any other part of the stick. 

 There is a purlin rim (see fig. 5, s) of 8x10 inch timber, 

 put together like the plate-rim, bolted or fastened with an 

 iron stirrup under the middle of the hip rafters, which 

 plate-rim supports the intermediate rafters. The hips may 

 be tied to the intermediate rafters by long rods half way 

 between the plate and the purlin, if deemed necessary from 

 the size of the roof (r). The north section of the roof 

 (fig. 5) is represented as uncovered, showing the plate (p), 

 purlin (s), tie-rod (r) and bridging between plate and pur- 

 lin and the two sets of bridging above purlin, etc. It will 

 be noted that, in this form of roof, the roof-boards act as a 

 powerful tie to hold it all together, each nail holding to the 

 extent of its strength, thus supplementing the strength of 

 the plate-rim or bottom chord. 



It will be seen by fig. 5 that there is a drive-way, fifteen 

 feet wide, through the center of the principal story from 



