FOUNDING; FOUNDRY 475 



proportions, for producing castings of peculiar qualities ; as also for coal, coke, sands, 

 clay, powdered charcoal, and cow-hair for giving tenacity to the loam mouldings. 



2. One or more coke ovens. 



3. A workshop for preparing the patterns and materials of the moulds. It should 

 contain small edge millstones for grinding and mixing the loam, and another mill 

 for grinding coal and charcoal. 



4. A vast area, called properly the foundry, in which the moulds are made and filled 

 with the melted metal. These moulds are in general very heavy, consisting of two 

 parts at least, which must be separated, turned upside down several times, and replaced 

 very exactly upon one another. The casting is generally effected by means of largo 

 ladles or pots, in which the melted iron is transported from the cupola where it is 

 fused. Hence the foundry ought to be provided with cranes, having jibs moveable in 

 every direction. 



5. A stove in which such moulds may be readily introduced, as require to- be 

 entirely deprived of humidity, and where a strong heat may be uniformly maintained. 



6. Both blast and air furnaces, capable of melting speedily the quantity of cast-iron 

 to be employed each day. 



7. A blowing machine to urge the fusion in the furnaces. 



Fig. 991, represents the general plan of a well-mounted foundry. 



a, is a cupola furnace ; it is capable of containing 5 tons of cast iron. 



', is a similar furnace, but of smaller dimensions, for bringing down If ton. 



a", is a furnace like the first, in reserve for great castings. 



b b b b, a vast foundry apartment, whose floor to a yard in depth, is formed of 

 sand and charcoal powder, which have already been used for castings, and are ready 

 for heaping up into a substratum, or to be scooped out when depth is wanted for the 

 moulds. There are besides several cylindrical pits, from 5 to 7 yards in depth, 

 placed near the furnaces. They are lined with brick-work, and are usually left full 

 of moulding sand. They are emptied in order to receive large moulds, care being 

 had that their top is always below 'the orifice from which the melted metal is tapped. 



These moulds, and the ladles full of melted metal are lifted and transported by 

 the arms of one or more men, when their weight is moderate ; but if it be considerable, 

 they are moved about by cranes, whose vertical 

 shafts are placed at c, d, e, in correspondence, so 

 that they may upon occasion transfer the load 

 from one to another. Each crane is composed 

 principally of an upright shaft, embraced at top 

 by a collet, and turning below upon a pivot in a 

 step ; next of a horizontal beam, stretched out 

 from nearly the top of the former, with an 

 oblique stay running downwards, like that of a 

 gallows. The horizontal beam supports a move- 

 able carriage, to which the tackle is suspended 

 for raising the weights. This carriage is made 

 to glide backwards or forwards along the beam 

 by means of a simple rack-and-pinion mechanism, 

 whose long handle descends within reach of the 

 workman's hand. 



By these arrangements in the play of the 

 three cranes, masses weighing 5 tons may be transported and laid down with the 

 greatest precision upon any point whatever in the interior of the three circles traced 

 upon^. 991, with the points c, d, e, as centres. 



c, d, e, are the steps, upon which the upright shafts of the three cranes rest and 

 turn. Each shaft is 16 feet high. 



//, is the drying stove, having its floor upon a level with that of the foundry. 



f f, is a supplementary stove for small articles. 



g g tf , are the coking ovens. 



h is the blowing machine or fan. 



i, is the steam-engine, for driving the fan, the loam-edge stones, 



7c, and the charcoal mill. 



*', are the boiler and the furnace of the engine. 



#, workshop for preparing the loam and other materials of moulding. 



I, is the apartment for the patterns. 



The pig-iron, coals, &c., are placed either under sheds or in the open air, round the 

 above buildings ; where are also a smith's forge, a carpenter's shop, and an apartment 

 mounted with vices for chipping and rough cleaning the castings by chisels and files. 



Such a foundry may be erected upon a square surface of about 80 yards on each side, 

 and will be capable, by casting in the afternoon and evening of each day, partly in, 



