SULPHUR AND ITS EXTRACTION. 



487 



Calcarelle. — The earliest system adopted in Sicily was the cal- 

 carelle. This consisted simply of a stack of ore six to fifteen feet 

 square, built in a ditch three or four inches deep, and whose floor was 

 beaten hard and sloped to a single point, permitting the molten sul- 

 phur to flow out by an opening termed the morto. In building the 

 stack, care was taken to put the largest pieces of ore at the bottom, 

 selecting lumps of gradually diminishing size as the top was ap- 

 proached. The mass was ignited at the summit. The construction of 

 the stack usually occupied two days ; on the third day the sulphur 

 escaped by the morto, and on the fourth the calcarelle was pulled 

 down. The air necessary for the combustion of a portion of the sul- 

 phur (to afford the heat required to smelt the remainder) was freely 

 admitted at all sides ; only the mineral in the center of the heap was 

 heated without actual contact with the air, so that its sulphur was 

 melted out instead of being burned (oxidized). Consequently about 

 6,700 pounds of sulphur mineral were needed to afford 38.5 pounds of 

 sulphur, or a yield of 5*7 per cent ; as the ore contained thirty-five 

 per cent of sulphur, the consumption of sulphur as fuel was 1,960 

 pounds, in order to extract 385 pounds. In addition, the immense vol- 

 umes of sulphurous acid emitted from the stack caused a terrible de- 

 struction of the agricultural crops in the neighborhood. 



Calcarone. — Nearly all the sulphur prepared in Sicily is now ex- 

 tracted by the calcarone (or calcherone, as it may also be spelled). 

 This, as is shown in Figs. 1 and 2, is formed by building a circular 



Fig. 1. 



stone wall on an inclined sole. In front is the morto or outlet, hav- 

 ing a height of four to six feet, and a width of two feet ; over it is 

 erected a wooden shelter for the workman in charge. Galcaroni may 

 contain from two hundred to four hundred casse (each casse being 

 equivalent to about six tons, and giving twelve to sixteen hundred- 

 weight of sulphur). The durability of the calcarone is governed by 



