366 BOOK IX. 



The upper bellows-board is joined to the head of the bellows in the 

 following way. An iron plate'', a palm wide and one and a half palms long, 

 is first fastened to the head at a distance of three digits from the end ; from 

 this plate there projects a piece three digits long and two wide, curved 

 in a small circle. The other side has a similar plate. Then in the same 

 part of the upper board are fixed two other iron plates, distant two digits 

 from the edge, each of which are six digits wide and seven long ; in each 

 of these plates the middle part is cut away for a little more than three 

 digits in length and for two in depth, so that the curved part of the plates 

 on the head corresponding to them may fit into this cut out part. From 

 both sides of each plate there project pieces, three digits long and two 

 digits wide, similarly curved into small circles. A little iron pin is passed 

 through these curved pieces of the plates, like a little axle, so that the upper 

 board of the bellows may turn upon it. The Uttle axle is six digits long and a 

 little more than a digit thick, and a small groove is cut out of the upper 

 board, where the plates are fastened to it, in such a manner that the Uttle axle 

 when fixed to the plates may not fall out. Both plates fastened to the 

 bellows-board are affixed by four iron nails, of which the heads are on the 

 inner part of the board, whereas the points, clinched at the top, are 

 transformed into heads, so to speak. Each of the other plates is fastened 

 to the head of the bellows by means of a nail with a wide head, and by two 

 other nails of which the heads are on the edge of the bellows-head. Midway 

 between the two plates on the bellows-board there remains a space two 

 palms wide, which is covered by an iron plate fastened to the board by 

 little nails ; and another plate corresponding to this is fastened to the head 

 between the other two plates ; they are two palms and the same number 

 of digits wide. 



The hide is common to the head as to all the other parts of the body ; 

 the plates are covered with it, as well as the front part of the upper bellows- 

 board, and both the bows and the back of the head of the bellows, so that the 

 wind may not escape from that part of the bellows. It is three palms and as 

 many digits wide, and long enough to extend from one of the sides of the 

 lower board over the back of the upper ; it is fastened by many T-headed 

 nails on one side to the upper board, and on the other side to the head of 

 the bellows, and both ends are fastened to the lower bellows-board. 



In the above manner the bellows is made. As two are required for each 

 furnace, it is necessary to have twelve bellows, if there are to be six furnaces 

 in one works. 



Now it is time to describe their framework. First, two sills a little 

 shorter than the furnace wall are placed on the ground. The front one of 

 these is three palms wide and thick, and the back one three palms and two 

 digits. The front one is two feet distant from the back wall of the furnace, and 

 the back one is six feet three palms distant from the front one. They are set into 

 the earth, that they may remain firm ; there are some who accomplish this by 

 means of pegs which, through several holes, penetrate deeply into the ground. 



TTiis whole arrangement could be summarized by the word " hinge." 



