BOOK IX. 367 



Then twelve short posts are erected, whose lower ends are mortised into 

 the sill that is near the back of the furnace wall ; these posts are two feet 

 high, exclusive of the tenons, and are three palms and the same number of 

 digits wide, and two palms thick. A slot one and a half palms wide is cut 

 through them, beginning two palms from the bottom and extending for a 

 height of three palms. AU the posts are not placed at the same intervals, the 

 first being at a distance of three feet five digits from the second, and likewise 

 the third from the fourth, but the second is two feet one palm and three 

 digits from the third ; the intervals between the other posts are arranged in 

 the same manner, equal and unequal, of which each four pertain to two 

 furnaces. The upper ends of these posts are mortised into a transverse 

 beam which is twelve feet, two palms, and three digits long, and projects 

 five digits beyond the first post and to the same distance beyond the fourth ; 

 it is two palms and the same number of digits wide, and two palms thick. 

 Since each separate transverse beam supports four bellows, it is necessary to 

 have three of them. 



Behind the twelve short posts the same number of higher posts are 

 erected, of which each has the middle part of the lower end cut out, so that 

 its two resulting lower ends are mortised into the back sill ; these posts, 

 exclusive of the tenons, are twelve feet and two palms high, and are five palms 

 wide and two palms thick. They are cut out from the bottom upward, the 

 slot being four feet and five digits high and six digits wide. The upper ends of 

 these posts are mortised into a long beam imposed upon them ; this long 

 beam is placed close under the timbers which extend from the wall at the 

 back of the furnace to the first long wall ; the beam is three palms wide 

 and two palms thick, and forty-three feet long. If such a long one is 

 not at hand, two or three may be substituted for it, which when joined together 

 make up that length. These higher posts are not placed at equal distances, 

 but the first is at a distance of two feet three palms one digit from the second, 

 and the third is at the same distance from the fourth ; whUe the second is at a 

 distance of one foot three palms and the same number of digits from the 

 third, and in the same manner the rest of the posts are arranged at equal 

 and unequal intervals. Moreover, there is in every post, where it faces the 

 shorter post, a mortise at a foot and a digit above the slot ; in these mortises 

 of the four posts is tenoned a timber which itself has four mortises. Tenons 

 are enclosed in mortises in order that they may be better joined, and they 

 are transfixed with wooden pins. This timber is thirteen feet three palms 

 one digit long, and it projects beyond the first post a distance of two palms 

 and two digits, and to the same number of palms and digits beyond the 

 fourth post. It is two palms and as many digits wide, and also two palms 

 thick. As there are twelve posts it is necessary to have three timbers of this 

 kind. 



On each of these timbers, and on each of the cross-beams which are laid 

 upon the shorter posts, are placed four planks, each nine feet long, two palms 

 three digits wide, and two palms one digit thick. The first plank is five feet 

 one palm one digit distant from the second, at the front as well as at the back. 



