8 Field Museum of Natural History 



some years after. It operated on the same principle 

 as the modern furnace, but as it did not have the hot 

 blast, did not utilize the furnace gases and lacked other 

 refinements, its efficiency and capacity were low. Its 

 most noticeable features were the massive construction, 

 the large flame at the top and the primitive character 

 of the equipment. 



The massive pyramidal structure near the center 

 of the model is the furnace. It is built of limestone 

 and encloses a small central shaft similar in outline to 

 that of a modern furnace. It is built at the foot of a 

 cliff so that the charge may be fed at the top without 

 hoisting. The top of the furnace is connected with the 

 top of the cliff by a bridge over which the charge of 

 ore, charcoal and limestone is wheeled in barrows. The 

 top is enclosed in an iron hood which is provided with 

 a smokestack so that the charging platform may be 

 sufficiently free from gases to permit men to work 

 there. The top is open and the gases generated in the 

 furnace escape and burning continuously form a large 

 flame visible for miles. Iron and slag form as in the 

 modern furnace and are drawn off in a similar manner 

 although the provisions for this are more complex than 

 they are in modern furnaces. At the right of the model 

 is the wooden blowing engine called the TUBS. At 

 the extreme right is the water w^heel which drives the 

 blovving engine. This engine consists of two wooden 

 upright cylinders, the tubs, provided with wooden 

 pistons and appropriate valves. The tubs deliver their 

 air to a third tub above which acts as a receiver. From 

 this receiver an underground conduit takes the air 

 direct to the tuyeres which feed it to the furnace. The 

 output is low. Such a furnace as the model represents 

 might yield thirty tons of pig iron a day. 



III. THE CATALIAN FORGE. The model at 

 the left represents the Catalian forge which was in 



[20] 



