SULPHUR AND ITS EXTRACTION. 489 



as to effect the maximum degree of fusion with a minimum of oxida- 

 tion. When the operation is conducted during winter, the product is 

 less abundant, and of inferior quality. After the charge is exhausted, 

 a new one can not be introduced till the mass has cooled down, occupy- 

 ing a period of ten days to a month, according to the size of the cal- 

 carone. The discharging has to be done slowly and cautiously, on 

 account of the sulphurous fumes liberated. The consumption of sul- 

 phur (as fuel) in the heating is about fifty per cent of the total amount 

 contained in the ore. Thus, to obtain one ton of sulphur, there is 

 consumed as fuel about another ton, worth say five pounds, and per- 

 forming a duty which could be much more satisfactorily accomplished 

 by two hundred-weight of coal, costing perhaps five shillings. 



A great improvement in the Sicilian calcarone has been introduced 

 by P. Le Neve Foster, and worked with good results, showing an in- 

 crease of yield of thirty per cent above the ordinary plan. Accord- 

 ing to his description, the waste heat from an ordinary calcarone, after 

 all the sulphur has been run off, is utilized to heat to the required 

 temperature the charge of ore placed in his kiln, and, as soon as the 

 moisture has been driven off and the heat is great enough, the charge 

 is fired from the tojs. The combustion, fed with hot air containing 

 some sulphurous-acid gas, is very slow, hence the loss of sulj^hur by 

 burning is less than when, as in the ordinary calcarone, the ore has to 

 be heated entirely by the combustion of the sulphur. The apparatus 

 (shown in Fig. 3, prepared from a drawing kindly furnished me by the 

 inventor) consists essentially of three parts : 1. The flue, or conductor 

 of heat ; 2. The kiln, in which the ore is treated ; 3. The chamber for 

 the condensation of the sulphur that is volatilized during the fusion, 

 and in which it is collected. 



The kiln may be of any suitable form to contain two charges of 

 ore, but a rectangular chamber is found to be most convenient, with 

 floor sloping toward the front. The chamber consists of four walls, 

 preferably not covered with an arch, as affording greater facility for 

 charging and discharging. The kiln communicates, by means of a flue, 

 A, with the back of an ordinary calcarone, B, which furnishes the heat 

 necessary for melting the sulphur from the one contained in the kiln, 

 C. The upper portion of the calcarone should be covered with a layer 

 of genese (spent ore), so as to prevent the dispersion of heat by any 

 other channel than that offered by the flue, A, which is provided with 

 a damper, D, so as to regulate the admission of heated air by openings, 

 E, at the upper back part of the kiln. A rectangular opening, F, is 

 left in the front wall of the kiln, from which the melted sulphur is run. 

 This opening, if of sufficient size, may serve for discharging the spent 

 ore at the termination of the fusion. From the upper part of the 

 opening, and also in the front wall, slightly above the level of the floor, 

 flues, G, communicate with a horizontal passage, H, which is made 

 large enough to serve as a condensation chamber, on the walls of which 



