BOOK IX.

369

fastened in it. The pipe is made of a rolled copper or iron plate, a foot andtwo palms and the same number of digits long ; the plate is half a digitthick, but a digit thick at the back. The interior of the pipe is three digitswide, and two and a half digits high in the front, for it is not absolutely round ;and at the back it is a foot and two palms and three digits in diameter. Theplate from which the pipe is made is not entirely joined up, but at the frontthere is left a crack half a digit wide, increasing at the back to three digits.This pipe is placed in the hole in the furnace, which, as I said, was in themiddle of the wall and the arch. The nozzles of the bellows, placed in thispipe, are a distance of five digits from its front end.

The levers are of the same number as the bellows, and when depressedby the cams of the long axle they compress the bellows. These leversare eight feet three palms long, one palm wide and thick, and the ends areinserted in the slots of the posts ; they project beyond the front posts to adistance of two palms, and the same distance beyond the back posts in orderthat each may have its end depressed by its two cams on the axle. Thecams not only penetrate into the slots of the back posts, but project threedigits beyond them. An iron pin is set in round holes made through bothsides of the slot of each front post, at three palms and as many digits from thebottom ; the pin penetrates the lever, which turns about it when depressedor raised. The back of the lever for the length of a cubit is a palm and adigit wider than the rest, and is perforated ; in this hole is engaged a barsix feet and two palms long, three digits wide, and about one and one-halfdigits thick; it is somewhat hooked at the upper end, and approaches thehandle of the bellows. Under the lever there is a nail, which penetratesthrough a hole in the bar, so that the lever and bar may move together. Thebar is perforated in the upper end at a distance of six digits from the top ;this hole is two palms long and a digit wide, and in it is engaged the hook ofan iron implement which is a digit thick. At the upper part this implementhas either a round or square opening, like a link, and at the lower end ishooked ; the link is two digits high and wide and the hook is three digits long ;the middle part between the link and the hook is three palms and twodigits long. The link of this implement engages either the handle of thebellows, or else a large ring which does engage it. This iron ring is a digit thick,two palms wide on the inside of the upper part, and two digits in thelower part, and this iron ring, not unlike the first one, engages thehandle of the bellows. The iron ring either has its narrower part turnedupward, and in it is engaged the ring of another iron implement, similarto the first, whose hook, extending upward, grips the rope fastened to theiron ring holding the end of the second lever, of which I will speakpresently ; or else the iron ring grips this lever, and then in its hook isengaged the ring of the other implement whose ring engages the handle of thebellows, and in this case the rope is dispensed with.

Resting on beams fixed in the two walls is a longitudinal beam, at adistance of four and a half feet from the back posts ; it is two palms wide,