232 CEMENTS, LIMES, AND PLASTERS. 



partly coarse and partly fine. This is repeated till the kiln is filled 

 to the top, which required about 10 tons of coal and 15 cords of stone, 

 equal to 1500 bushels of cement. Then the fire is started at the bottom 

 and gradually works its way upward until the whole mass is glowing 

 with heat. After two or three days the gate or door in the bottom is 

 opened and through it the burned cement rock is drawn to the amount 

 of 250 to 300 bushels per day, fresh coal and rock being constantly 

 added to keep the kiln full to the top. One cord of cement rock makes 

 100 bushels of cement." 



Hies states that two types of kilns are in use at the Cummings 

 plant at Akron, Erie County, N. Y. Of seventeen kilns in use there 

 at the time of his visit, eight were of rectangular cross-section, 9 by 22 

 feet in area, with a height of 34 feet. The remaining nine were cir- 

 cular in cross-section, with a diameter of 9 feet and a height of 34 

 feet. 



Two types of kilns are in use in the Fort Scott district, Kansas. The 

 more common type is cylindrical, 10 to 12 feet in diameter and 30 to 40 

 feet in total height. The lower 10 feet or so is of stone, on which is set 

 the kiln proper. This is constructed of ^-inch sheet iron, lined with 

 successive layers of coal ashes, clay, common brick and fire-brick. These 

 kilns are drawn daily, and yield 60 to 75 barrels of cement each per 

 day. The fuel used is slack coal, either Arkansas semi-bituminous from 

 Poteau or Huntingdon or a very sulphurous local coal which under- 

 lies the cement rock at Fort Scott. The coal is fed with the rock, and 

 is used at the rate of 30 to 35 Ibs. per barrel of cement, equal to a fuel 

 consumption of 11.3 to 13.2 per cent on the weight of cement produced. 

 At a three-kiln plant the burning is managed by five men two feeding 

 and three drawing the kilns. 



At one of the Fort Scott plants four flame-kilns are also in use. These 

 have separate fireplaces, so that the fuel and cement do not come into 

 contact. Lump coal must be used for these kilns, and they are said 

 to be more expensive, both in labor and fuel, than the type above 

 described. 



The kilns at the plant of the Howard Cement Company, in Georgia, 

 are of the familiar dome type commonly used in lime and natural- 

 cement burning, and are six in number. Four are jacketed with steel 

 and lined with fire-brick, the space between the jacket and the lining 

 being filled with clay. The two remaining kilns differ from these only 

 in the fact that in place of the steel jacket their exterior surfaces are 

 laid up with rock. These rock- jacketed kilns are said to be somewhat 

 more satisfactory than those of the steel- jacketed type. 



