368 



BOOK IX. 



for each separate plank is placed outside of the posts. The third is at the 

 same distance from the fourth, but the second is one foot and three digits 

 distant from the third. In the same manner the rest of the eight planks are 

 arranged at intervals, the fifth from the sixth and the seventh from the eighth 

 are at the same distances as the first from the second and the third from the 

 fourth ; the sixth is at the same distance from the seventh as the second 

 from the third. 



Two planks support one transverse plank six feet long, one foot wide, one 

 palm thick, placed at a distance of three feet and two palms from the back 

 posts. When there are six of these supporting planks, on each separate one 

 are placed two bellows ; the lower bellows-boards project a palm beyond 

 them. From each of the bellows-boards an iron ring descends through a hole 

 in its supporting plank, and a wooden peg is driven into the ring, so that the 

 beUows-board may remain stationary, as I stated above. 



The two bellows communicate, each by its own plank, to the back of a 

 copper pipe in which are set both of the nozzles, and their ends are tightly 



A — Front sill. B — Back sill. C — Front posts. D — Their slots. E — Beam 



IMPOSED UPON THEM. F — HiGHER POSTS. G — ThEIR SLOTS. H — BeAM IMPOSED UPON 



THEM. I — Timber joined in the mortises of the posts. K — Planks. L — Transverse 



SUPPORTING PLANKS. M — ThE HOLES IN THEM. N — PiPE. O — ItS FRONT END. P — ItS 



REAR END. 



