246 The Philippine Journal of Science 1914 



the molten iron forward so that it spills out over the lip of the 

 tap hole into the ladle. 



The iron is poured from the ladle directly into the molds, a 

 cover of floating charcoal preventing the oxidation of the surface 

 of the metal while in the ladle. The plowpoints are cast hollow 

 by pouring around a suitable clay core. The only parts of the 

 casting which necessitate the use of molding sand are the pro- 

 jecting rods on the bottom of the shares by which the shares 

 are clamped to the plowbeam. To provide for these, the share 

 molds have a core box into which molding sand, consisting of 

 a pulverized mixture of clay and charcoal, is pressed around 4 

 small sticks, so placed that the spaces left upon their removal 

 serve as molds for the rods. After each pour, the mold is 

 opened, the casting removed, and the surfaces of the mold care- 

 fully inspected for broken places. All cracks and flaws are 

 patched up with clay, and the surfaces are painted with a char- 

 coal paint. 



The smelting continues as long as the furnace works well or 

 until no more iron can be brought down, ordinarily for a period 

 of from twelve to fifteen days. Occasionally a furnace cannot 

 be made to work properly, and is allowed to "die" after- four or 

 five days' trial. In such cases, the lining of the crucible is 

 removed and a new lining built up. After a run, the furnace 

 is cleaned and relined, and is then ready to be again blown in. 



Capacity of the furnaces. — The following table shows the pro- 

 duction in pairs " and in kilograms per day and per smelting run 

 for 4 furnaces. The first three are ordinary runs, while the 

 last is the record run for the district. It will be noted that there 

 is little evidence of a decrease in production toward the end of 

 the runs. This is due to the tendency to stop the smelting 

 whenever, after the usual length of time, the furnace shows 

 signs of working badly, instead of continuing until no more iron 

 is reduced. 



'^ Plowshares (lipias) are made in three sizes and plowpoints (sudsuds) 

 in one size (Plate V). They are counted and sold in pairs (pares), which 

 consist in the cases of the points and each of the two smaller plowshares 

 of two castings, but each one of the larger plowshares constitutes a pair. 

 A first-class pair (1 large plowshare) weighs 3.2 kilograms; a second- 

 class pair (2 smaller plowshares), 4.0 kilograms; a third-class pair (2 

 plowshares), 2.5 kilograms; and a pair of points weighs 5 kilograms. 



