492 THE POPULAR SCIENCE MONTHLY. 



distilled sulphur, placed outside the furnace. The apparatus is gen- 

 erally employed on rich material, or on that obtained from the calca- 

 roni ; but it is also applicable to ores which are too poor to burn in 

 the calcaroni, though the profit in that case must be small. The heat 

 generated in the do2opione is likely to encourage chemical action be- 

 tween the sulphur and any lime carbonate that may chance to be pres- 

 ent in the mineral, creating a further loss of sulphur. The pots are 

 charged and discharged by opening the lids, which are kept luted dur- 

 ing the distillation. The volatilized sulphur is conducted by the cast- 

 iron tub, b, into the receptacle, c, over which a small current of cold 

 water constantly flows, reducing the sulphur to a fluid condition ; it 

 then escapes into the dish, d, beneath, whence it can be ladled into 

 the molds. The pots last for about three hundred working-days, and 

 the furnace serves about the same time with a couple of repairings. 

 The workman is expected to turn out one hundred pounds of clean 

 sulphur from every one hundred and nine pounds of calcarone sulphur. 



The principle underlying the use of calcium chloride is that, while 

 raising the boiling-point of water to about 239° Fahr. (115° C), the 

 melting-point of sulphur, it is cheap and inert in the presence of sul- 

 phur. The water to be used in the melting process is charged with 

 sixty-six jDer cent of the calcium chloride, and heated to boiling, in 

 which state it is run into the vessel containing the sulphur to be melted. 

 No doubt the sulphur is efticiently melted, but the very slight differ- 

 ence in specific gravity between the sulphur and the associated impuri- 

 ties, from which it had been melted out, practically precludes any real 

 separation taking place. Consequently, the process is virtually a fail- 

 ure, as I am assured by those who have worked it. 



At the Rabbit Hole mines, Humboldt County, Nevada, advantage 

 is taken of the liquidity of sulphur at 232° Fahr. (111° C), to use 

 steam at sixty to seventy pounds pressure for melting the sulphur out 

 of the gangue. The apparatus employed consists of a cylindrical iron 

 vessel, about ten and a half feet high, divided into an upper and a lower 

 compartment, by means of a horizontal sheet-iron diaphragm perforat- 

 ed with one-fourth-inch holes. As soon as the upper compartment is 

 charged with ore (about two tons), steam is introduced for about half 

 an hour, and the sulphur, liquefied by the heat, flows down through the 

 diaphragm into the lower compartment, kept at the proper heat by 

 injection of steam, and escapes by an outlet, opened at intervals into 

 a receptacle placed outside. When water commences to flow out with 

 the sulphur, steam is injected at full pressure for a few minutes, to 

 clear out as much as will come, and the solid residue is afterward re- 

 moved through a door above the diaphragm. Each charge requires 

 about three hours for its treatment. The process is adapted to ores 

 which, for poverty and other reasons, can not be economically worked 

 by calcaroni, or other recognized methods. 



While hot water and steam have no solvent action upon sulphur, 



